On November 25, 1970 Elmer Davis, Jr. and Ralph Wynn, Jr. were tried by a jury on a charge of possessing an unregistered firearm (sawed-off shotgun) in violation of 26 U.S.C. Sec. 5861(d). Statements previously given by each defendant were introduced into evidence at the joint trial. Neither defendant testified or offered evidence. The two defendants were convicted and sentenced to five years imprisonment. They appeal separately on different grounds.

The activity leading to the arrest of the appellants began in Detroit, Michigan. Davis and Wynn obtained an automobile, vehicle registration card, and credit cards from one Paul Hunter. The companions then drove through Ohio on their way to visit friends of Davis in Kentucky. According to statements later given by the men, the car had a flat tire in Ohio, and when they opened the car trunk to get the spare tire, they discovered and examined a sawed-off shotgun. After arriving in Kentucky, the appellants spent several days visiting various people.

On June 11, 1969, they drove to the house of Enos Banks. Earlier that day, Davis had made disparaging remarks about Banks. Davis and Banks began to argue and according to Banks' testimony, Wynn reached into the open car trunk, pulled out the shotgun and pointed it at him. Banks claims that he then left and went to his brother-in-law's house to get a pistol. He later observed Wynn carrying the weapon into the building which was sectioned into several apartments, including Banks'. Apparently some occupant of the building threw the weapon out a window where it was later retrieved by a child and given to police.

About 9:30 P.M. in the evening following the incident with Banks, state police arrested Davis and Wynn on a suspicion of automobile theft. The suspects were detained in the Perry County jail near Hazard, Kentucky. Later that night the police notified the nearest federal agents, located 80 miles away in Pineville, Kentucky, of possible firearms and Dyer Act violations. Sometime during the following morning, June 12, 1969, a federal agent came to Hazard from Pineville. After advising the suspects of their rights, the agent interviewed the men and took statements from each suspect before noon that day. On June 13, 1969, the men were taken before the part-time United States Magistrate in Pineville.

* In appealing his conviction, appellant Davis advances three allegations of error. First, it is suggested that an inadequate Miranda warning was given; second it is contended that an unnecessary delay occurred before he was taken before a United States Magistrate; and third, it is alleged that there was no independent corroboration of the admission introduced against him.

Concerning the Miranda warning, appellant suggests that he was not clearly apprised of the fact that he could terminate any questioning, even after the questioning had begun, and request counsel at that time. Consequently, it is argued, there was no intelligent waiver of rights. This contention is without merit. The statement given by Davis begins with a recitation of rights and a waiver of those rights.1 In relevant part, that recitation states: "I understand that I have the right to remain silent and that I may invoke this right, or the right to consult a lawyer, at any time." While we could devise a more explicit statement declaring a suspect's right to rescind a waiver of rights and end questioning at any time, we conclude that the challenged statement provides an adequate and understanding apprisal of rights.

Appellant next contends that under Rule 5(a), Federal Rules of Criminal Procedure, the delay in taking him before a United States Commissioner was unreasonable and that therefore the district court should have excluded any statement made during this detention.2 The United States responds that since the statement was made within a couple of hours after the federal agent arrived at the jail, the delay was not unreasonable.

While the record is not precisely clear, the agent did arrive at the Perry County jail during the morning of June 12, 1969. Sometime before noon that day, Davis made his statement. There is no indication that appellant's statement was made involuntarily. Nor is there present here a lengthy interrogation which might suggest an invalid waiver of rights.3 Appellant's argument is that his statement should be excluded solely because of the delay in taking him before a commissioner.4

In Mallory v. United States, 354 U.S. 449, 77 S. Ct. 1356, 1 L. Ed. 2d 1479 (1957), the Supreme Court in an application of procedural Rule 5(a) made clear that a statement taken during an "unnecessary delay" in arraignment was inadmissible as evidence. But the relevant period of delay is measured from the time of arrest to the giving of the statement, and a period of illegal detention following the statement will not nullify a "prompt acknowledgement by an accused of his guilt. . . ." United States v. Mitchell, 322 U.S. 65, 64 S. Ct. 896, 88 L. Ed. 1140 (1944). Congress modified the Mallory rule of evidence by statute. 18 U.S.C. Sec. 3501(c). Under this statute a person's confession "shall not be inadmissible solely because of delay in bringing such person before a magistrate . . . if such confession is found by the trial judge to have been made voluntarily and if the weight to be given the confession if left to the jury and if such confession was made or given by such person within six hours immediately following his arrest or other detention. . . ."

Here, the appellant was arrested by state police on a suspicion of theft of an automobile. While the appellants had been held overnight in the county jail prior to the interview, there was no detention of the suspects by federal agents until the following morning. In applying Rule 5(a), we previously have indicated that ordinarily the relevant delay is measured from the commencement of federal detention. This rule applies where there is no proof of a "working arrangement" between state police and federal agents "for the purpose of aiding and abetting the federal officers in carrying on interrogation of the suspect in violation of Federal Rule 5(a) requiring prompt arraignment. . . ." United States v. Hindmarsh, 6 Cir., 389 F.2d 137, 146 (1968). Similarly, we think any delay for purposes of Sec. 3501(c) must be measured from the beginning of the federal detention.

There is no suggestion here of a working arrangement between federal and state authorities. It is apparent that the statements were made well within six hours following the federal detention. And since mere delay is the sole basis for the contention that the confession is inadmissible, that contention must fail under Sec. 3501(c).

Finally, appellant Davis argues that there was no independent corroboration of his extrajudicial admission made after commission of the crime. It is well established that a conviction must rest upon a firmer foundation than the mere confession of the accused. Opper v. United States, 348 U.S. 84, 75 S. Ct. 158, 99 L. Ed. 101 (1954); Smith v. United States, 348 U.S. 147, 75 S. Ct. 194, 99 L. Ed. 192 (1954). The corroboration requirement applies equally to an accused's admission of essential facts or elements of the offense subsequent to the crime. Opper v. United States, supra, 348, U.S. at 90, 75 S. Ct. 158. The purpose of the corroboration principle is to prevent "errors in convictions based upon untrue confessions alone." Warszower v. United States, 312 U.S. 342, 347, 61 S. Ct. 603, 606, 85 L. Ed. 876 (1941).

The facts admitted in Davis' statement suggest that the appellant exercised such dominion and control over the weapon so as to constitute actual possession.5 Davis argues that the statement is uncorroborated because the independent evidence by itself does not establish that he had either actual or constructive possession of the weapon. But "corroborative evidence does not have to prove the offense beyond a reasonable doubt, or even by a preponderance, as long as there is substantial independent evidence that the offense has been committed, and the evidence as a whole proves beyond a reasonable doubt that defendant is guilty." Smith v. United States, supra, 348 U.S. at 156, 75 S.Ct. at 199.

Even though the independent evidence need not actually establish the offense, the prosecution must introduce substantial evidence tending to show that Davis possessed the shotgun.6 As the Supreme Court stated:

All elements of the offense must be established by independent evidence or corroborated admissions, but one available mode of corroboration is for the independent evidence to bolster the confession itself and thereby prove the offense "through" the statements of the accused. Id., at 156, 75 S.Ct. at 199.

The essential facts admitted by Davis are that he knew that the weapon was in the car he was driving and that he handled the weapon at various times. Here, the extrinsic proof of possession implicates the appellant and strongly suggests a clear connection between Davis and the weapon. Davis and Wynn drove the car to Banks' house. Banks had seen Davis driving the car. Another witness, Jenkins, had seen Davis driving the car prior to the incident at Banks' house. Davis and Banks argued and Wynn pulled the shotgun from the trunk of the car and pointed it at Banks. The trunk was already open so that Wynn needed only to reach into the trunk and take the weapon.

From these facts a jury could reasonably infer that Davis knew that the weapon was in the car he was driving and that he intended to exert dominion over the weapon. The extrinsic evidence here clearly corroborates the admissions. "It is sufficient if the corroboration supports the essential facts admitted sufficiently to justify a jury inference of their truth." Opper v. United States, 348 U.S., at 93, 75 S.Ct., at 164.7II

We turn now to the case of the other appellant, Ralph Wynn, Jr. This appellant argues that the introduction into evidence of co-defendant Davis' extrajudicial admission inculpating Wynn violated the rule of Bruton v. United States, 391 U.S. 123, 88 S. Ct. 1620, 20 L. Ed. 2d 476 (1968), and requires the reversal of Wynn's conviction. At trial, counsel for Wynn did not object to the introduction into evidence of Davis' statement, but asked that the jury be instructed not to consider the statement in determining Wynn's guilt or innocence. The district court complied with this request, and Wynn's counsel expressed satisfaction.

On appeal, Wynn maintains that the court's conduct was reversible error. Ordinarily, of course, a Court of Appeals will not review the conduct of the trial court unless a party makes known to the trial court the action objected to and the grounds for the objection. Rule 51, Federal Rules of Criminal Procedure. Apparently, appellant urges that the trial court's conduct constituted an error affecting substantial rights and thus should be recognized as "plain error." Rule 52(b), Federal Rules of Criminal Procedure. The Bruton rule, applied retroactively in Roberts v. Russell, 392 U.S. 293, 88 S. Ct. 1921, 20 L. Ed. 2d 1100 (1968), seeks to avoid a serious flaw in the fact-finding process at trial. Any violation of that rule might, therefore, present an appropriate occasion for the recognition of a plain error.

But even assuming a violation of the Bruton rule in the instant case, (raised only by appellant Wynn) such violation would be harmless error.8 Harrington v. California, 395 U.S. 250, 89 S. Ct. 1726, 23 L. Ed. 2d 284 (1969). The evidence against Wynn was overwhelming. There was his own statement admitting facts constituting possession. Witness Banks testified that Wynn at one time stated that he had a shotgun and at another time grabbed the shotgun and pointed it at Banks. Witness Jenkins saw Wynn in the back seat of the car holding the shotgun. When Wynn was arrested, he had a shotgun shell in his pocket. On the basis of this record, we conclude that Wynn would have been convicted without the admission of Davis' statement and that if any error occurred, it was indeed harmless "beyond a reasonable doubt." Chapman v. California, 386 U.S. 18, 87 S. Ct. 824, 17 L. Ed. 2d 705 (1967).

Affirmed.