ROCHESTER, N.Y. (AP) _ A man convicted on weapons charges may have been plotting to help Colombian drug kingpin Carlos Lehder escape from federal prison, a prosecutor said.

Assistant U.S. Attorney Anthony Bruce said investigators believe Dominic Taddeo was involved in planning a jailbreak attempt for Lehder, a key figure in the Medellin drug cartel in the early 1980s.

Investigators reached that conclusion after searching a storage locker rented by Taddeo in Allentown, Pa., Bruce said.

''We found stuff in the Pennsylvania locker that led us to put two and two together and determine there might be an attempt being planned to get Carlos Lehder out of Marion,'' he said.

Lehder is serving a 140-year sentence at the federal prison in Marion, Ill., for drug trafficking and conspiracy.

Bruce would not be more specific about what was found in the locker.

Taddeo was sentenced last week to 17 years in prison for illegal possession of weapons and for jumping bail on those weapons charges two years ago.

A federal grand jury in Rochester is hearing allegations that Taddeo was involved in three mob-related killings in the early 1980s. Taddeo, 33, has never been charged in those killings.

Bruce said he will recommend that Taddeo serve his sentence at Marion, considered the nation's highest-security prison.

''As I understand Marion, you do not leave your cell unless you're in the company of two guards,'' Bruce said. ''You might get somebody out of Marion with the Russian army, but short of that, you're hurting.''