Staley, Van Dusen and Adams, Circuit Judges.
This appeal challenges a June 22, 1971, district court order denying an application of plaintiff under 28 U.S.C. § 2255 for vacation of sentence imposed on September 23, 1966 (Criminal No. 239-66, D.N.J.).
The application requests that the conviction and sentence be vacated "because there is no factual basis for conviction and the charges are not supported by a true bill of the Grand Jury according with the Federal Constitution, Amendment V."*fn1 After a careful review of the criminal file, including the transcripts of the July 25, 1966, guilty plea of petitioner to two counts of the indictment alleging violation of 18 U.S.C. § 2113(a) and of the subsequent September 23, 1966, sentencing proceeding, we have concluded that on this record there is no merit in the above-quoted contentions raised by the petition.*fn2 See McMann v. Richardson, 397 U.S. 759, 90 S. Ct. 1441, 25 L. Ed. 2d 763 (1970); Costello v. United States, 350 U.S. 359, 76 S. Ct. 406, 100 L. Ed. 397 (1956); United States ex rel. Grays v. Rundle, 428 F.2d 1401 (3d Cir. 1970), and cases there cited.
However, the transcript of the July 25, 1966, proceeding discloses that the district court did not comply with Rule 11 of the Federal Rules of Criminal Procedure*fn3 at the time it accepted the guilty plea on the basis of which the sentence was entered.*fn4 At least this portion of the mandate of that rule, which was summarized, in part, as follows in Woodward v. United States, 426 F.2d 959, 962 (3d Cir. 1970), was not explained to petitioner:*fn5
"First, the court must satisfy itself that the defendant understands the nature of the charge. Routine questioning or a single response by the defendant that he understands the charge is insufficient. To satisfy itself that the defendant actually does comprehend the charges, the court must explain the meaning of the charge and what basic acts must be proved to establish guilt." [Footnotes omitted.]
Santobello v. New York, 404 U.S. 257, 261-262, 92 S. Ct. 495, 30 L. Ed. 2d 427 (1971); Compare: Kress v. United States, 411 F.2d 16 (8th Cir. 1969).
Under these circumstances, the district court is required to hold a hearing to determine whether Christinzio's plea of guilty was in fact entered voluntarily with an understanding of the nature of the charges,*fn6 since the "files and records of the case" do not "conclusively show that the prisoner is entitled to no relief." See 28 U.S.C. § 2255; George v. United States, 421 F.2d 128 (2d Cir. 1970). Although the transcripts of the July 25, 1966, proceeding and of the sentencing proceeding make clear that petitioner was not a stranger to the federal criminal courts, the record before the district court did not permit a finding or conclusion that the Government had sustained the burden imposed on it by the failure of the sentencing judge to comply with the above-mentioned Rule 11 requirements. See Halliday, supra note 6.
The June 22, 1971, order will be vacated insofar as it denied the application of petitioner and the case will be remanded to the district court for further ...