Thomas F. Boyd appeals his conviction for assaulting a federal officer (18 U.S.C. § 111). He argues that due process was violated when the trial judge failed to hold a hearing after learning at the time of sentencing that Boyd’s court-appointed attorney had once worked as a federal marshal and was acquainted with two prosecution witnesses.

Boyd admitted that he knew these facts before his trial. Boyd has not suggested any failure of his trial counsel, either in preparation or presentation. None is pointed out to us by Boyd’s new counsel on appeal.

The district judge, in rejecting Boyd’s contentions, stated that defense counsel had done a “very, very good” job. The trial judge is in the best position to pass *1371 on the sufficiency of counsel. We decline to hold that the trial judge must hold a sufficiency-of-counsel hearing upon the assertion of facts as flimsy as those put forth here.

Affirmed.