A man has been convicted of first-degree murder in a killing that arose from a dispute over a Beatles poster, although his defense lawyer said he was bullied into a role in the killing.

Donald L. Smiley-Lyle, 19, faces more than 25 years in prison after being convicted Friday by a jury in Spokane County Superior Court, Deputy Prosecutor Stephen W. Garvin said. Sentencing was set for Dec. 20.

Testimony during the two-week trial showed Smiley-Lyle helped strangle Robert "Bud" Johnson, 45, whose body was pulled from the Spokane River on March 18, 2006.

"I'm happy there's one more monster off the streets," Johnson's half brother, Brett Krop, said after the verdict.

A key witness against Smiley-Lyle was Robert A. Entel, 20, who pleaded guilty in an agreement with prosecutors and was sentenced to 25 years. Without the deal he could have faced life behind bars.

Prosecutors said the two young men plotted to kill Johnson as a favor to Entel's cousin, Kathryn B. Kelly, 31, who lived briefly with the older man — a relationship that ended with him asking her to return a framed and autographed "Hard Day's Night" Beatles poster he'd given her.

When Kelly refused, Johnson and a friend reportedly drove to Entel's house and took the poster. Entel and Smiley-Lyle then planned and carried out the killing of Johnson, prosecutors said.

Kelly was acquitted of first-degree murder after a trial in June.

Defense lawyer Douglas A. Boe portrayed Entel as a bully who instigated the attack on Johnson and took advantage of Smiley-Lyle.

The two became friends at Morning Star Boys Ranch, where they were placed as teenagers, and later practiced martial arts and fantasized about creating their own militia. After being kicked out of the Marines and the National Guard, Entel returned to Spokane and again sought out Smiley-Lyle, Boe said.