This appeal from convictions of murder in the first degree [11 Del.C. § 636(a)(2)]1 and *818rape [11 Del.C. § 763] raises numerous issues, primarily the issue of the authority of a Deputy Attorney General to withdraw his offer of a plea bargain after it was accepted by the defendant.
I.
The defendant was indicted for first degree murder and rape. Some time before trial, the Deputy Attorney General in charge of the case and defense counsel negotiated a plea bargain under which the defendant would enter guilty pleas to murder in the second degree [11 Del.C. § 635]2 and rape; and upon the entry of such guilty pleas and sentences thereon, the State would enter a nolle prosequi dismissing the first degree murder charge. The offer was documented by the Deputy Attorney General and, several days later, defense counsel communicated the defendant’s acceptance of the offer.
Several weeks later and prior to the entry of a plea by the defendant, for reasons “never delineated in writing to the defendant or his counsel” (or made clear to this Court), the Deputy Attorney General orally advised counsel that the State was unilaterally withdrawing from the plea bargain agreement. The defendant took the position that the State was obligated to perform the plea bargain agreement.
Prior to the plea bargain negotiations, the defendant had filed the following motions: (1) to quash the indictment because prejudicial publicity made a fair and impartial trial in Delaware impossible; (2) to quash the first degree murder count of the indictment because the governing Statutes providing for capital punishment were unconstitutional; and (3) for change of venue. Motions were also filed relating to the defense of insanity and for discovery and inspection.
Following the State’s withdrawal from the plea bargain, the defendant moved (1) for specific performance of the plea bargain agreement; (2) to suppress all oral statements and a written statement taken from the defendant and any evidence derived therefrom; (3) to suppress evidence allegedly utilized to elicit the said statements and to connect the defendant to the crime.
Prior to trial, the Superior Court denied the motions for specific performance of the plea bargain, for dismissal of the indictment, for change of venue, and for suppression.
The jury found the defendant guilty as charged and, after denial of post-trial motions, the defendant was sentenced to death for first degree murder and life imprisonment for rape. A stay of execution was issued pending this appeal.
Any other facts necessary to state will be set forth in the portion of this opinion to which they relate.
II.
The defendant contends that the Trial Court erred in denying the motion for specific performance of the plea bargain agreement. He insists that the State should have been, and should still be, obliged to *819honor the plea bargain offered by it and accepted by the defendant.3
The defendant asserts various theories in support of his contention that the plea bargain agreement should be specifically enforced. Basically, the defendant’s arguments rest on theories of (1) breach of contract, and (2) breach of the pledge of public faith by the prosecutor. While the defendant cites cases based on one or both of those theories, in which relief was provided for a broken plea bargain agreement, each case is distinguishable from the instant case in one controlling aspect — the element of reliance.
The defendant acknowledges the importance of “reliance” in this connection:
“Like the contract theory for upholding plea bargains, the pledge of public faith rationale also relies upon the element of detrimental reliance by the criminally accused as a basis for granting specific performance of the plea bargain. . . . ”
The case law throughout emphasizes the requisite of reliance. For example, in Santobello v. New York, 404 U.S. 257, 263, 92 S.Ct. 495, 30 L.Ed.2d 427 (1971), the United States Supreme Court recognized that specific performance may be available as the remedy for a broken plea bargain agreement; the agreement in that case, however, was breached by the prosecution after the defendant had pleaded guilty to a lesser-included offense in reliance upon the prosecutor’s promise not to make a sentencing recommendation.4 Indeed, in all cases which have come to our attention, affording relief for breach by the prosecution of a plea bargain, the sequence of events has been (1) reliance, and (2) breach. See United States v. Paiva, 294 F.Supp. 742 (D.D.C.1969) (defendant pleaded guilty and furnished information in exchange for the promise of dismissal of remaining charges); State v. Wolske, 280 Minn. 465, 160 N.W.2d 146 (1968) (defendant pleaded guilty in reliance upon prosecutor’s promise to dismiss other charges); State v. Thomas, 61 N.J. 314, 294 A.2d 57 (1972) (defendant pleaded guilty in exchange for promise of dismissal of remaining charges). See also State v. Brockman, 277 Md. 687, 357 A.2d 376 (1976); State v. Hingle, 242 La. 844, 139 So.2d 205 (1962).
Two Delaware decisions bearing on the question of broken plea bargains emphasize the factor of reliance: Hinckle v. State, Del.Supr., 189 A.2d 432 (1963) and Hamilton v. State, Del.Supr., 285 A.2d 807 (1971). In Hinckle, the defendant was indicted for a felony which carried a maximum sentence of 3 years. Pursuant to an agreement with the State, the defendant pleaded guilty to a lesser-included offense carrying an indeterminate sentence. The Trial Court, however, summarily disregarded the agreement and imposed a 7 year prison sentence. This Court found such refusal to consider the agreement, after reliance thereon by the defendant, an abuse of discretion. 189 A.2d at 435. In Hamilton,5 too, this Court de-*820dined to permit a defendant to be deprived of the benefit of a plea bargain agreement upon which he had relied in entering a guilty plea.
The defendant contends that the State obtained valuable information from him by reason of the plea agreement; yet, the defendant never specifies what information was revealed or valuable constitutional right relinquished. Such abstract contentions are insufficient to support this ground. Compare United States v. Paiva, supra (defendant identified the specific bonds he had forged); and People v. Prado, 81 Misc.2d 710, 365 N.Y.S.2d 943 (1975) (defendant stipulated that if he passed polygraph test he would be released on his own recognizance, but if he failed the results of the test would be admissible in court).
We hold that the State may withdraw from a plea bargain agreement at any time prior to, but not after, the actual entry of the guilty plea by the defendant or other action by him constituting detrimental reliance upon the agreement.
In the instant case, there is no showing that the defendant entered a plea or took any other action constituting detrimental reliance upon the plea bargain. Accordingly, there was no error in the Trial Court’s denial of specific performance of the agreement.
III.
The defendant contends that Superior Court Criminal Rule 24(b)6 is unconstitutional in that it requires the defendant to exercise all of his peremptory challenges to the jury before the State must challenge any, thus affording the State a double opportunity to challenge in violation of fundamental fairness. The defendant suggests rotation as a more fair procedure, but offers no authority condemning the Rule 24(b).
Peremptory challenges are privileges which are subject to reasonable regulation as to the manner of their exercise. See Stilson v. United States, 250 U.S. 583, 40 S.Ct. 28, 63 L.Ed. 1154 (1919); Swain v. Alabama, 380 U.S. 202, 85 S.Ct. 824, 13 L.Ed.2d 759 (1965). While the idea of rotation of peremptory challenges may commend itself for future rule-making consideration, we cannot say that the time-honored procedures prescribed by Rule 24(b) are unreasonable.
IY.
A.
During the trial, and over the objection of the defendant, a police lieutenant and a police corporal sat with the prosecutor during the selection of the jury and assisted him in the process. These officers were the chief police investigators and principal witnesses for the State.
There is no showing of actual or inherent prejudice in the action of the police witnesses in this case. We conclude, therefore, that there was no denial of due process or reversible error by reason of the Trial Court’s rejection of the motion addressed to this situation which, we understand, has been permitted frequently in the past.
For future reference, however, it is announced that the practice of permitting police witnesses to assist in jury selection is disapproved. The practice tends to ingratiate the police witnesses in the eyes of the jury; and such apparent association with the “convening” of the Trial Court tends to enhance unfairly the credibility of the po*821lice witnesses and denigrate that of defense witnesses. See Bailey v. State, Del.Supr., 363 A.2d 312, 316-17 (1976).
B.
The defendant also complains that the Trial Court refused to sequester the two police officers and to require them to testify first in the State’s case, in accordance with Grace v. State, Del.Supr., 314 A.2d 169 (1973). On the record before us, we find no abuse of discretion in violation of Grace as to either the sequestration or the order of proceeding.
V.
As other grounds of appeal, the defendant asserts:
(1) That the Trial Court erred in denying the defendant’s motion for change of venue. As to this ground, we find no abuse of discretion. Parson v. State, Del. Supr., 222 A.2d 326 (1966).
(2) That the Trial Court erred in admitting into evidence certain documentary and physical evidence seized during an allegedly invalid consent search. As to this ground, under the totality of the circumstances on the record before us, we find no reversible error. Schneckloth v. Bustamonte, 412 U.S. 218, 93 S.Ct. 2041, 36 L.Ed.2d 854 (1973); c. f., State v. Herhal, Del.Super., 307 A.2d 553 (1973).
(3) That the Trial Court denied defendant due process in that the voir dire examination of jurors did not meet the essential demands of fairness. As to this ground, we find no abuse of discretion by the Trial Court. Parson v. State, Del.Supr., 275 A.2d 777 (1971); McCoy v. State, Del. Supr., 361 A.2d 241 (1976).
(4) That the Trial Court erred in admitting State’s evidence and prosecutor’s remarks to the jury regarding character and reputation of the victim in this rape case. We find no reversible error as to this ground.
(5) That the Trial Court erred in refusing to declare a mistrial when State witness testified that defendant had been the subject of prior investigation and was suspected of other similar offenses. We find that this statement was volunteered by the witness and was sufficiently cured by cautionary instruction to the jury. Johnson v. State, Del.Supr., 311 A.2d 873 (1973).
(6) That the Trial Judge committed error in admitting into evidence certain maps. We conclude that if error, it is not reversible error.
(7) That the Trial Court erred in permitting the principal police officers to testify a second time during the State’s case in chief. We find no abuse of judicial discretion here. C. f., Pepe v. State, 3 Storey 417, 53 Del. 417, 171 A.2d 216 (1961).
VI.
The defendant attacks the constitutionality of 11 Del.C. § 4209, the governing Statute providing for capital punishment in first degree murder cases at the time of this offense.
This question has been settled by this Court in State v. Spence, Del.Supr., 367 A.2d 983 (1976). Under that decision, the death sentence imposed upon this defendant must be set aside and a sentence of life imprisonment without benefit of parole must be imposed upon him.
******
Accordingly, the judgment below is affirmed, except that the cause is remanded with instructions to strike the death sentence imposed upon the murder charge and to substitute in lieu thereof a sentence of life imprisonment without benefit of parole.