A South Oakland man was sentenced to prison yesterday for killing a lifelong friend because he thought the man was having an affair with his estranged wife.

Allegheny County Common Pleas Judge Kathleen A. Durkin ordered Shawn Scott, 43, to spend 8 to 18 years in prison. In June, a jury convicted Mr. Scott of third-degree murder for shooting his neighbor, Aaron "Rocky" Townsend, through a screen door in a jealous rage on Sept. 10, 2006.

Mr. Townsend, 44, was pronounced dead after a relative found him on his kitchen floor with multiple gunshot wounds.

Mr. Scott's father, William Scott, who lives a few houses away from where Mr. Townsend was killed, told police that the two men had been close since they were children.

At the time of the shooting, Mr. Scott had broken up with his wife, Latosha Scott, of Lawrenceville, and moved in with his father. A cell phone number on his wife's phone and taunting remarks she testified she had made led Mr. Scott to suspect that Mr. Townsend and his wife were having an affair.

She also told the jury her taunts were not true and that she and Mr. Townsend never had an affair.

After Mr. Townsend was pronounced dead, Mr. Scott called his father and said, "I finally killed him," police said. William Scott said his son did not mention the victim by name, but he knew his son meant Mr. Townsend.