During his testimony, Jeffrey Wilson painted a dark picture of Army Maj. David Shannon and his wife, Joan. Wilson told jurors that the couple had a swinging lifestyle and that they often had sex with other people.
Shannon was shot to death in 2002. Investigators say his wife planned her husband's death and convinced her teenage daughter, Elizabeth Shannon, to shoot him.
Prosecutors believe Joan Shannon wanted her husband dead so she collect insurance money and run away to be with Wilson, a soldier who worked at Womack Army Medical Center.
During his testimony, Wilson also claimed that he slept with Joan Shannon after Maj. Shannon came up with the idea. He testified that he also took photos of him and Joan Shannon together and that the Shannons thought nothing of it.
"She had other partners," Wilson said. "As long as it wasn't serious, (her husband) didn't mind."
Wilson also said that he believed Joan Shannon was falling in love with him. He said that when Maj. Shannon died, the defendant was not upset.
Wilson also suggested that he was just with Joan Shannon for money to buy a motorcycle.
"I'd tell her what she wanted to hear to get what's at the end of the rainbow -- her to co-sign for my motorcycle," Wilson said.
The prosecution rested its case Friday. If convicted, Joan Shannon could go to prison for life. Elizabeth Shannon pleaded guilty and faces a maximum of 31 years in prison.