‘CSI: Las Vegas’ Season 15: Dean McDermott Guest Stars As A Sex Offender In Episode 12! Did He Kill A Whole Family?

Dean McDermott is accused of killing a whole family in "CSI: Las Vegas" Season 15.

Sarah Sidle reopens a 10-year-old murder-suicide case thanks to a memory recovered by the massacre's lone survivor. Then 5 years old, Abby lost her memories the night her whole family was shot during a camping trip but when she suddenly remembers something, she insists that her father didn't kill her mom and sister.

Despite ruffling the feathers of several people, DB Russell allows Sarah to dig into the case again. He also allows her to dig up Abby's father to determine if he had been drugged the night of the killing.

With the new evidence, they determined that he was in fact given a knock out drug, therefore giving Sarah the chance to fully investigate the case again.

With his previous record as a child sex offender, Garth (McDermott) gets implicated as the murderer. His fingerprint was also found in one of the sleeping bags.

The team figures out that he was actually the older girl's biological father. He had only met up with the mother before they left for the camping trip to demand a meeting with his daughter.

Hoping to open her mind up to more memories of that night, Sarah and Greg recreate the scene of the crime. As Abby goes through the set up, she recovers all of her memories, as well as more details of the man she saw that night.

Realizing that the bearded man she remembers is actually an elk hunter, the "CSI: Las Vegas" season 15 team visits the nearest hunting club in the area and got the information from the local taxidermist.

With a positive ID, police pursued the suspect, only to find him shot in the head. The chemical found in the hid gun, however, brings the team back to the taxidermist.

He confesses to the crime but tells Sarah that it was his friend (the new victim) who killed the family. In turn, he supposedly was the one who tucked the girls into their sleeping bags.

Sarah, however, doesn't buy the twisted confession. Abby remembered the bearded man tucking her in after being shot but the taxidermist didn't have a single hair on his face.

"CSI: Las Vegas" season 15 ends with Abby finally being able to forgive his father while rewriting her family history at the same time.