Trevor Quan is an patient of Dr. David Yarzick. When Booth and Sweets asked Dr. Yarzick about Claire Serrano he mentions a fellow patient had become very, very attached to her. "Sounds like a stalker to me," Booth says. Booth and Sweets then interview the "stalker," Trevor . Trevor plays the violin as he talks about his beloved, claiming the victim was afraid of her husband. Booth then spots linseed oil in Trevor's violin case. Later Hodgins explains the linseed oil in the grave does not match the linseed oil in Trevor's case.