A 16-year-old who said he had suffered years of physical and mental abuse and "didn't have anyplace to go" has been convicted of voluntary manslaughter in the ambush slaying of his father.

Jurors, who had been asked to find the youth guilty of first-degree murder or conspiracy to commit murder, apparently felt Richard J. Jahnke "was driven to a certain state of mind that caused him to act the way he did," defense attorney James Barrett said.

The Laramie County District Court jury returned its verdict late Saturday night. Jahnke faces up to 20 years in prison at sentencing next month.

The youth's father, Richard J. Jahnke, 38, an Internal Revenue Service agent, was shot with a 12-gauge shotgun Nov. 16 outside the garage of his home. Prosecutors alleged that Richard and his 17-year-old sister, Deborah, waited to ambush their father after he returned from an anniversary dinner with his wife, Maria.

Deborah Jahnke, charged with conspiracy to commit first-degree murder and aiding and abetting, is scheduled to stand trial March 7.

Richard Jahnke told the jury Friday he had wanted to kill his father for years but was pushed to act when he feared his father would beat him and his sister, perhaps to death.