The appellant was given a twenty-year sentence for bank robbery and a five-year sentence for interstate transportation of a stolen motor vehicle. While serving the first sentence, he sought to have the other sentence vacated by a proceeding under 28 U.S.C.A. § 2255. The district court denied relief.

A proceeding under 28 U.S.C. A. § 2255 can be maintained only if the applicant is serving the sentence which is under attack. Under special circum *180 stances a motion made to vacate a sentence during imprisonment for a different offense may be considered as an application for a writ of coram nobis. Young v. United States, 5th Cir. 1964, 337 F.2d 753. No special circumstance is here shown.

Appellant’s ground for relief is based upon the fact that the consent to the transfer of the case under Rule 20 Fed. Rules Crim. Proc. 18 U.S.C.A., was signed by the Assistant United States District Attorney rather than by the District Attorney himself. There is no merit in the contention.

The order of the district court is

Affirmed.