HARTFORD, Conn. — A leader of a Massachusetts motorcycle club known as The Undertakers has pleaded guilty to murder in the slaying of a truck driver from Maine.

Frank Morrill, 26, entered the plea Tuesday in the fatal shooting of Douglas W. Gentle, who was ambushed at a Southington rest stop Sept. 11, 1992.

Gentle, 39, was traveling from New York to his home in Houlton when he pulled into the truck stop off Interstate 84. He offered a ride to a woman, who stashed her belongings in the truck and went to take a shower. When the woman returned, Gentle and the truck were gone.

His body was found the next day, but the truck had vanished.

Morrill said he helped a couple of friends steal the big rig but was not the triggerman.

He told the court that Gentle’s body was dumped in Chelsea, Mass., and the truck was driven to New Hampshire, where Morrill and others scrubbed away identifying marks on the truck. The truck wasn’t discovered by police until a year later in Massachusetts.

Morrill is scheduled to be sentenced May 13. He is expected to receive a 40-year prison term.