What follows is an opinion from a United States Court of Appeals.
Your task is to identify the issue in the case, that is, the social and/or political context of the litigation in which more purely legal issues are argued. Put somewhat differently, this field identifies the nature of the conflict between the litigants. The focus here is on the subject matter of the controversy rather than its legal basis.
Your task is to determine the specific issue in the case within the broad category of "criminal - federal offense".

Opinion:
Lamar WILLIAMS, Petitioner-Appellant, v. UNITED STATES of America, Respondent-Appellee
No. 15961.
United States Court of Appeals Sixth Circuit.
March 19, 1965.
Lamar Williams, in pro. per.
Thomas L. Robinson, U. S. Atty., Dwayne D. Maddox, Asst. U. S. Atty., Memphis, Tenn., Herbert J. Miller, Jr., Asst. Atty. Gen., Dept, of Justice, Criminal Division, Washington, D. C., on brief for appellee.
Before CECIL, O’SULLIVAN and PHILLIPS, Circuit Judges.
PER CURIAM.
The petitioner filed a motion to vacate sentence pursuant to 28 U.S.C. § 2255, which was disallowed by the district court, and petitioner has appealed.
Petitioner and three codefendants were charged with robbing a bank in Oakland, Tennessee, on February 3, 1961, and placing the bank employees’ lives in jeopardy by use of a dangerous weapon, in violation of 18 U.S.C. § 2113. Petitioner was represented by counsel at the hearing and entered a plea of guilty.
This is the same bank robbery that was involved in Olive v. United States, 327 F.2d 646 (C.A. 6), cert. denied, 377 U.S. 971, 84 S.Ct. 1653, 12 L.Ed.2d 740. The facts in the present case are substantially similar in many respects to the facts as set forth in some detail in the opinion of this court in the Olive case, and will not be repeated here.
The order of the district judge contains the following summary of the former proceedings:
“The petitioner entered pleas of guilty in this Court to the offenses charged against him and completely admitted his guilt of the offenses in open court.
“The United States of America has filed a motion to dismiss the petition and supported that motion with Affidavits of Special Agents of the Federal Bureau of Investigation and also the complete official court reporter’s transcript of all proceedings in this case. The Court recalls vividly this entire matter. The petitioner, along with his accomplices, were apprehended in a getaway car with the money obtained during the robbery and the gun used in the holdup was found in the car minutes after the robbery of The Oakland Deposit Bank, Oakland, Tennessee, on February 3, 1961.
“As shown by the transcript, the indictments were read to the petitioner in full by the Clerk in open court. At the time the pleas of guilty were entered in this cause, Lamar Williams was represented by competent counsel who was acquainted with his family. The Court questioned him as to his guilt of the offenses charged against him. Subsequently, on the date of sentencing, March 29, 1961, the Court again questioned petitioner as to his pleas of guilty and afforded him every opportunity to make a statement and asked him if the District Attorney made a true factual statement of his case.”
We find that this summary is fully supported by the record.
The judgment of the district court is affirmed. Machibroda v. United States, 368 U.S. 487, 82 S.Ct. 510, 7 L.Ed.2d 473; Olive v. United States, supra; United States v. Orlando, 327 F.2d 185 (C.A. 6), cert. denied, 379 U.S. 825, 85 S.Ct. 50, 13 L.Ed.2d 35.

Question: What is the specific issue in the case within the general category of "criminal - federal offense"?

Choices:
murder
rape
arson
aggravated assault
robbery
burglary
auto theft
larceny (over $50)
other violent crimes
narcotics
alcohol related crimes, prohibition
tax fraud
firearm violations
morals charges (e.g., gambling, prostitution, obscenity)
criminal violations of government regulations of business
other white collar crime (involving no force or threat of force; e.g., embezzlement, computer fraud,bribery)
other crimes
federal offense, but specific crime not ascertained

Answer: 4