OPINION ON APPELLANT’S PETITIONS FOR DISCRETIONARY REVIEW
Appellant was convicted of voluntary manslaughter and attempted voluntary manslaughter and sentenced by the court to 40 years imprisonment for each conviction, the terms to run concurrently. Appellant’s convictions were affirmed by the El Paso Court of Appeals. Alvarado v. State, 804 S.W.2d 669 (Tex.App.1991). We affirm the judgment of the court of appeals.
In his petitions for discretionary review, appellant alleges his Fifth and Fourteenth Amendments rights under the U.S. Constitution were violated. Appellant contends the State Judicial Police of Chihuahua, Mexico, were acting as agents for the El Paso police, when they obtained his confession without first advising him of his constitutional rights as set forth in Miranda v. Arizona,1 and therefore, federal and state exclusionary rules require his confession to be excluded from trial.2 No question of *19whether the admission of the confession violates any of the provisions of article 38.22 of the Texas Code of Criminal Procedure is presented in this appeal.3 The El Paso Court of Appeals ruled Miranda warnings were inapplicable to confessions obtained outside the U.S. and determined further that there was no agency relationship between the Mexican police and the El Paso police because the Mexican authorities had an “independent, albeit concurrent, basis for the arrest and production of the challenged confession, and that the deterrent effect intended by the various federal and state exclusionary rules would not be served by the suppression of this appellant’s confession.” 804 S.W.2d at 672. We granted appellant’s petitions for discretionary review to determine whether appellant’s confession to Mexican officials was admissible in the absence of Miranda warnings.
Appellant, a U.S. citizen, was involved in an altercation outside Chico’s Tacos on Alameda Street in the city of El Paso on April 26, 1989. After appellant shot and killed Ricardo Gomez and shot and wounded Augusto Medina, he fled from El Paso to Juarez, Mexico. Following police procedure, the El Paso police notified the state police authorities in Juarez, Mexico that appellant was a suspect for a murder committed in the U.S. and was believed to be residing in Juarez. Acting in part on the El Paso police tip, the Mexican State Judicial Police in Juarez apprehended appellant.
Following the Mexican Code of Criminal Procedure, the Mexican State Police obtained a written statement from appellant in which he confessed to his crimes in the United States. Mexican police turned appellant and his confession over to the Mexican Chief of Immigration for deportation. U.S. officials were unaware of appellant’s apprehension and confession until appellant was presented to U.S. Immigration officials in El Paso. Appellant was subsequently tried and convicted of both crimes based in part on the confession obtained by the Mexican State Police.
Appellant complains the admission of the confession violates his Fifth and Fourteenth Amendment rights because the Mexican police, acting as agents for the El Paso police, obtained a confession from him without first reading the Miranda warnings.4 This appeal presents two questions for us to resolve; first whether Miranda is *20applicable to actions by foreign authorities outside the United States, and second whether the factual finding of no agency by the trial court and court of appeals was supported by sufficient evidence.
This is a case of first impression for this Court.5 We begin with the question of whether Miranda applies to activities of foreign officials outside the United States. Prior to obtaining the statement from Appellant, the Mexican police informed appellant of his rights under the Laws of Mexico. These rights would not be sufficient in themselves to meet the requirements of Miranda. According to the record, an accused in Mexico has the right to appoint any person, not necessarily an attorney, to assist or defend himself, but there is no right to appointed counsel during the interrogation process. An attorney will not be appointed until the court appearance. We note that appellant makes no claim nor do we find upon our own examination of the record that the incarceration procedure employed by the Mexican police violated any of the Laws of Mexico.
The Fifth Amendment provides in part that no person “shall be compelled in any criminal case to be a witness against himself...” In order to effectuate the Fifth Amendment’s directive, the Supreme Court in Miranda v. Arizona, held:
The prosecution may not use statements, whether exculpatory or inculpatory, stemming from custodial interrogation of the defendant unless it demonstrates the use of procedural safeguards effective to secure the privilege against self-incrimination. By custodial interrogation, we mean questioning initiated by law enforcement officers after a person has been taken into custody or otherwise deprived of his freedom of action in any significant way ... The defendant may waive effectuation of these rights, provided the waiver is made voluntarily, knowingly, and intelligently.
384 U.S. 436, 444, 86 S.Ct. 1602, 1612, 16 L.Ed.2d 694 (1966). The purpose for the exclusion of evidence for violations of Miranda is to prevent governmental coercion by substantially deterring future violations of the constitution. Connelly, 479 U.S. 157, 167 and 170, 107 S.Ct. 515, 521-22 and 523. Miranda warnings are not themselves constitutionally mandated, but rather they are procedural safeguards or prophylactic measures to prevent governmental coercion. Connecticut v. Barrett, 479 U.S. 523, 528, 107 S.Ct. 828, 831-32, 93 L.Ed.2d 920 (1987); Michigan v. Tucker, 417 U.S. 433, 444, 94 S.Ct. 2357, 2363-64, 41 L.Ed.2d 182 (1974); Cooper v. Dupnik, 924 F.2d 1520 (9th 1991). “Indeed, the Fifth Amendment privilege is not concerned ‘with moral and psychological pressures to confess emanating from sources other than official coercion.’ ” Connelly, 479 U.S. at 170, 107 S.Ct. at 523 citing, Oregon v. Elstad, 470 U.S. 298, 105 S.Ct. 1285, 84 L.Ed.2d 222 (1985) (emphasis added). “Miranda protects defendants against government coercion leading them to surrender rights protected by the Fifth Amendment; it goes no further than that.” Connelly, 479 U.S. at 170, 107 S.Ct. at 523.
Other jurisdictions which have considered the matter before us today have held, as a general rule, that Miranda warnings are not essential to the validity of a confession which has been obtained in a *21foreign country by foreign officials.6 The rationale for such a rule was explained in Kilday v. United States, “the United States Constitution cannot compel such specific, affirmative action by foreign sovereigns, [such as requiring the Miranda warnings,] so the policy of deterring so-called “third degree” police tactics, which underlies the Miranda exclusionary rule, is inapposite to [cases where a suspect is interrogated by foreign police authorities].” 481 F.2d 655, 656 (5th Cir.1973). We believe the rationale for the general rule is sound. Accordingly, we join these jurisdictions and hold the requisites of Miranda do not generally extend to other countries.
The clear import of Miranda is to require U.S. officials to notify accused persons of their constitutionally protected rights prior to any questioning. This prophylactic measure, protects our citizens from our state and our federal governmental actions. We know of no constitutional objective that would be served by extending Miranda to cases outside our borders. Because this is a question of interpretation of Miranda, and whether it applies, we fail to see how the state and federal exclusionary rules could differ. Our exclusionary rule contained in article 38.23 of the Texas Code of Criminal Procedure excludes evidence obtained, in this case, in violation of Miranda. See also Bodde v. State, 568 S.W.2d 344, 352-353 (Tex.Crim.App.1978) (en banc) (Article 38.23 is inapplicable where a private individual violated no Texas laws in conducting search.) Therefore, the seminal question is the applicability of Miranda and not whether this is an exception to the state or federal exclusionary rules. Contrast Garcia v. State, 829 S.W.2d 796 (Tex.Crim.App.1992) (plurality opinion).
Notwithstanding the general inapplicability of Miranda to confessions obtained by foreign officials, two exceptions have been carved out of the general rule. First, the confession will be excluded if the circumstances surrounding the confession shocks the conscience of an American Court. United States v. Heller, 625 F.2d 594, 599 (5th Cir.1980); Birdsell v. United States, 346 F.2d 775, 782 n. 10 (5th Cir.1965); United States v. Fernandez-Caro, 677 F.Supp. 893, 894-95 (S.D.Tex.1987) (Confession obtained by Mexican authorities through physical torture “shocked the *22conscience” of American Courts, and evidence obtained as a result of said confession held inadmissible); see generally United States v. Hawkins, 661 F.2d 436, 456 (5th Cir.1981); Zani v. State, 679 S.W.2d 144, 151 (Tex.App.—Texarkana 1984), rev’d on other grounds, 758 S.W.2d 233 (Tex.Crim.App.1988). In this case there is no indication from the record that appellant did anything but volunteer his confession to Mexican authorities, nor does he complain of anything unusual or shocking about the manner in which his statement was obtained.
Second, the confession will also be excluded when U.S. law enforcement personnel participate in the foreign interrogation or if the foreign authorities are acting as agents for their U.S. counterparts.7 United States v. Heller, supra; see Burdeau v. McDowell, 256 U.S. 465, 41 S.Ct. 574, 65 L.Ed. 1048 (1921); Bodde v. State, supra (evidence obtained by private individual who was not acting as government officer or acting as agent of law enforcement officers, was admissible and did not violate the Fourth Amendment); United States v. Morrow, 537 F.2d 120, 139 (5th Cir.1976); United States v. Chavarria, 443 F.2d 904 (9th Cir.1971); Zani v. State, 679 S.W.2d 144, 151 (Tex.App.—Texarkana 1984), rev’d on other grounds, 758 S.W.2d 120, 139 (Tex.Crim.App.1988); People v. McKinnon, 7 Cal.3d 899, 103 Cal.Rptr. 897, 500 P.2d. 1097 (1972). In these cases when law enforcement officials are present or when the foreign officials are acting as agents for their U.S. counterparts, the prophylactic protections afforded by Miranda will best be served by the exclusion of the confession.
A portion of appellant’s grounds for review are premised in part on the belief that the Chihuahua State Judicial Police were acting as agents for the El Paso Police Department. Were this true our inquiry would end here. Where an individual acts as an agent for law enforcement personnel, the agents are bound by our confession rules. See Cantu v. State, 817 S.W.2d 74 (Tex.Crim.App.1991) (plurality opinion) (Department of Human Services investigator was not agent for law enforcement officials and confession was admissible); Cates v. State, 776 S.W.2d 170 (Tex.Crim.App.1989) (Department of Human Services investigator was agent for law enforcement officials and confession was inadmissible without Miranda warnings); McCrory v. State, 643 S.W.2d 725, 734 (Tex.Crim.App.1982); compare Burdeau v. McDowell, 256 U.S. 465, 41 S.Ct. 574, 65 L.Ed. 1048 (1921) (Evidence wrongfully obtained by individuals unconnected with the government does not violate the Fourth Amendment); United States v. Morrow, 537 F.2d 120, 139 (5th Cir.1976) (Absent an agency relationship, the Fourth Amendment does not generally protect U.S. citizens from acts by foreign officials outside the domain of the United States); United States v. Verdugo-Urquidez, 494 U.S. 259, 265-67, 110 S.Ct. 1056, 1061, 108 L.Ed.2d 222 (1990) (Fourth amendment does not apply to American officials acting outside the U.S. in obtaining evidence from non-citizens).
We believe a determination of whether an individual is acting as an agent for U.S. law enforcement personnel is best left to the trial court at a suppression hearing. The term “agency” denotes a consensual relationship existing between two persons, by virtue of which one of them is to act for and on behalf of the other. Ackley v. State, 592 S.W.2d 606 (Tex.Crim.App.1980) (panel opinion); Thompson v. Schmitt, 115 Tex. 53, 274 S.W. 554, 557 (1925); Noble Exploration, Inc. v. Nixon Drilling Co., Inc., 794 S.W.2d 589, 592 (Tex.App.—Austin 1990, n.w.h.). The actual agency relationship may be express or implied from the parties’ conduct. Noble, supra. Naturally the law does not presume an agency relationship, and the per*23son alleging such a relationship has the burden of proving it. Buchoz v. Klein, 143 Tex. 284, 184 S.W.2d 271 (1944).
At a suppression hearing, the trial judge is the sole judge of the credibility of the witnesses and of the weight attributable to those witnesses. Meek v. State, 790 S.W.2d 618, 621 (Tex.Crim.App.1990); Cannon v. State, 691 S.W.2d 664, 673 (Tex.Crim.App.1985), cert. denied, 474 U.S. 1110, 106 S.Ct. 897, 88 L.Ed.2d 931 (1986). The judge may believe or disbelieve all or any part of a witness’s testimony. Meek, 790 S.W.2d at 620; Cannon, 691 S.W.2d at 673. His findings should not be disturbed absent a clear abuse of discretion. Meek, 790 S.W.2d at 620. In this case, the trial court implicitly found there was no agency relationship between the Mexican authorities and the El Paso police when he denied the suppression motion, and in light of the record, we cannot say in this case that this was a clear abuse of discretion.
There is no evidence that Texas authorities participated in the seizure of appellant in Mexico, nor is there any evidence that Texas authorities participated in the taking of the confession by the Mexican police.8 The court of appeals determined that the Mexican police had an independent reason for obtaining a confession from appellant, and therefore upheld the trial court’s implicit ruling that the Mexican authorities did not act as agents of the El Paso police.9 *24See Arcila v. State, 834 S.W.2d 357, 361 (Tex.Crim.App.1992) (emphasis added) (“Even if our own decision might have been different [than the court of appeals] on the question presented, we cannot accept the proposition that an appellate court’s judgment ought to be subject to reversal on such basis, at least when the evidence is sufficient to support it. Doing so only tends to undermine the respective roles of this and the intermediate courts without significant contribution to the criminal jurisprudence of the State.”) The evidence at the suppression hearing indicated that when a Mexican citizen commits a crime in the United States and flees to Mexico, that person can be tried in Mexico under Mexican law. Mexican law does not recognize American traditions of venue. This unusual situation may have convinced the trial court as well as the court of appeals that the Mexican police acted on their own behalf, and not on behalf of their American counterparts. While appellant is not a Mexican citizen, it appears to be the Mexican procedure to obtain voluntary statements from all persons arrested. The evidence also indicates that the Mexican authorities would not deport an individual to U.S. authorities if they did not believe he was guilty of the crime, thereby necessitating an opportunity for the individual to make a statement to Mexican authorities.10
In a further attempt to show that an agency relationship existed between these neighboring authorities, appellant contends that cooperation between El Paso police and Juarez police has created a joint venture arrangement. While a joint venture arrangement would also create an agency relationship, mere notification of the potential existence of a criminal in another police’s jurisdiction is not enough to create such a relationship. See, United States v. Heller, supra (tip by American officials did not create agency relationship); United States v. Derewal, 703 F.Supp. 372 (E.D.Pa.1989) (merely supplying tip to foreign law enforcement agency which then conducts an investigation and search leading to an American prosecution does not amount to a “joint venture”); contra, United States v. Emery, 591 F.2d 1266, 1268 (9th Cir.1978) (DEA and Mexican authorities carried out a coordinated drug surveillance and drug arrest in Mexico). Texas border officials consistently notify their Mexican counterparts when a fugitive crosses the border. We view this as good police practice, rather than evidence that establishes a joint venture relationship. If this alone were to create a joint venture relationship, our sister states’ police officers would become agents of our State’s law enforcement personnel simply because we notified them of the movement of a fugitive. This is clearly not the intended result, nor do we so conclude.
SUMMARY
We therefore hold that the requirements of Miranda v. Arizona do not apply to actions of foreign officials not acting as agents of American law enforcement personnel. After reviewing the evidence we also conclude that the trial court did not abuse its discretion in holding the Mexican officials were not agents of the El Paso police department. We further hold that the court of appeals did not err in affirming the ruling of the trial court.
The actions of the Mexican police in obtaining appellant’s confession without first obtaining his Miranda warnings is not vio-lative of the U.S. Constitution. Therefore the confession of appellant was not excludable on the basis of Tex.Code Crim.Proc. article 38.23 or the federal exclusionary *25rule. The judgment of the court of appeals is affirmed.