A one-time janitor who was sentenced last October to 20 years in prison for recruiting young Minnesota men to fight in Somalia is mentally competent to withdraw the appeal of his conviction and sentence, a federal judge has ruled.

U.S. District Judge Michael Davis said Mahamud Said Omar had a rational understanding of the proceedings against him and the waiver of the appeal was voluntary.

Omar, 46, was one of the key figures in the prosecution of Somali-Americans living in Minnesota who were involved in aiding Al-Shabab, a U.S.-designated terrorist group waging a civil war in Somalia.

Prosecutors said Omar helped with travel arrangements and supplied cash to some of the men who joined Al-Shabab.

The defense attorneys had argued he was a simple, part-time janitor at the Abubakar As-Saddique Islamic Center in Minneapolis when the alleged conspiracy began in 2007 and got caught up in the case by accident.

After the conviction, Davis asked Omar’s attorneys to file a notice of appeal with the Eighth Circuit Court of Appeals, which is standard procedure, said Andrew Birrell, one of Omar’s lawyers. But subsequently Omar objected and the case was referred back to Davis to determine whether Omar would be allowed to withdraw it.

In hearings in June and again Tuesday, Davis questioned Omar about his decision.

Steven C. Norton, a psychologist assigned by Davis to evaluate Omar, determined that Omar did not suffer from a major mental illness, according to a memorandum by Davis, issued Tuesday. Norton said Omar refused to answer any questions about his criminal case or his views on the appeal.

Birrell said that Omar tried to explain his position in court “and what I got out of it was he just wants it over. He wants to just do his time and be done with it.”