Trish appeared in the episode Pink Champagne on Ice. She was the killer of Ryan De Stefano.
Trish and Ryan were in league to get back at the casino by kidnapping Holly and blackmailing her boyfriend, magician Jack Hellion, to rob it.
However, Ryan remorselessly killed Cheryl - Holly's roommate, even laughing about it to Trish. Trish cared only for the money, and couldn't trust Ryan to not turn on her. So, she shot him in the back, took Holly herself, and left Ryan on the side of the road.