Model high-school student Trevor Beck dies in his prized sports car. His girl friend seems missing, but her smashed corpse is found in a tree by a desert road. The team soon realizes its' the site of illegal drag-races, in which more kids of their high-school are involved, especially fellow auto-shop pupils, and a street gang. Student Miyamoto Takahashi also has a job in a garage, Dr. Parayan's son Rishi dealt some drugs at school.
The case of two high school students, one dead and one missing, lead the CSIs into the underbelly of streetcar racing and a tangled web of deadly competition.
- "CSI" - "Internal Combustion" - Feb. 4, 2010
It is night and Sin City and we meet Trevor, 17, on Robbins' slab. Other than being dead, he's in good health. We also see him alive in intercuts driving a fancy car to high school. Robbins notes some abrasions on his right hand consistent with a recen fight, which we see. Except Trevor just collapsed. His internal organs are all ship shape. Robbins is stumped on COD. They open his skull and realize he has a massive cerebral edema with no obvious cause.
Brass interviews his mom. Recent bump to the head? Headaches? He had been grumpy she said. She's, understandably sad. She wonders if something or someone killed him. Brass doesn't know. Brass asks for info. Turns out he was a car nut with few friends. Catherine looks at his Facebook-type page which was full of pictures of his cars and Trevor's new girlfriend Cindy.
Catherine and Archie check out Cindy's info. She wasn't home. They find her via her cellphone, she's at school. Or at least her phone is. Sara goes to look for her. She finds Cindy's friend Renata at her locker. Which they share. She hasn't seen her, she figured she just went home because she was sad about Trevor. Sara finds Cindy's cell phone case in her locker.
Outside Sara and Nick go over Trevor's car which is a classic, tricked out with an electric motor. It's perfect other than a recent scratch. She finds anti-depressants and Cindy's phone in the passenger door. Nick works an electronic gizmo that tells interesting stuff about the car.
Back at HQ Sara goes through the numbers, pictures, texts, videos, and emails. She finds an old pic of perhaps a former boyfriend and a video of that boyfriend getting into a fight with Trevor.
Brass goes to visit him at his job at an auto parts store, his name is Leo. He claims he and Trevor had no beef and he let Trevor slide for hitting him. He admits Cindy used to be his "lady." Brass theorizes this is why Leo killed him and Cindy is missing. He freaks that Cindy is missing and doesn't seem to have known it. HIs alibi is work.
Ray, Catherine, Sara, and Stokes go over Trevor's x-rays. Essentially his brain was jammed into his spine. It's a rare skull deformity. Most people don't know they have it until they get whacked in the head, like Trevor was. The antidepressants made it worse. The diagnostics from his fancy car show he drove 14 miles before he went to school. Catherine has a bad feeling.
Greg goes to a scene where Cindy was found impaled on a tree. David says she also has lots of internal injuries. Greg and Nick see no sign of a struggle, tire treads, or anything. Greg says it's like she fell from the sky.
Hodges and Sara look over the body and realize she was hit by the car and her body went flying so they have to widen their search.
Greg and Nick find their stretch of road and investigate. Greg finds her skirt, which must've flown off on impact, not sexual assault after all. Then her shoes. And blood spatter. They take pictures revealing treads not visible to the nade eye. It shows two sets of treads side by side. They realize it was a drag race with Cindy at the finish line. One set of treads fits Trevor's car.
They go to a kid who gave Trevor the anti-depressants in exchange for his tutoring in auto shop. The kid says Trevor wasn't a racer and that the car was his baby. She explains giving Trevor the pills is a felony and she threatens the kid's dad who owns the pharmacy. The yellow car he says belongs to a Demon gang member.
Brass has heard of them: chop shops, narcotics etc. They go to the LVPD street rumble, it's supposed to help keep racers off the street and where a lot of the gang types hang out with their tricked out cars. Sara and Nick check out one yellow car. She chats with the owner about his fine car and notices a scratch on the front bumper. The kid pleads ignorant and then they spot Leo, who takes off running. They nab him.
Back at HQ Greg and Nick look over the car. Greg reminisces about his own joyride at age 12 with his gramps car. Nick says Leo's been involved with stuff like this before. The wheels and paint match Leo's cars. Only problem is Leo's car has plastic headlights and there was headlight glass at the scene.
Sara looks at video from a previous street rumble. Trevor was a racer. At the end of his race he gets serious whiplash, which is probably what killed him, accidentally. They realize that the person racing, and being beaten, by Trevor was Renata, who's car has the right yellow paint. They think maybe the desert was a rematch.
Sara visits Renata's uncle and legal guardian and auto shop teaher at an auto shop. They want to take a look at her car. The car is totally clean but the headlights are glass and the wheel widths are right. They also notice it's been painted recently. Her alibi is fast food with friends. She says she called Cindy at 1 because they always did. Renata can't believe they think she killed Cindy. They impound the car but uncle says Renata was at home and he was with her.
Hodges, Nick, and Wendy give the car the once over. Nick wants to rule out other drivers. Hodges finds gum under the steering wheel.
Sara looks into traffic jams, the cops, under Brass's direction go to look for car parts at chop shops that might've come from Renata's car. At the lab Greg, Wendy, and Hodges break down the parts. Greg finds an imprint of Cindy's sweater on the hood. Renata's guardian was a racer back in the day. Sara finds traffic footage of Renata in Trevor's car at the time of the race. Catherine pieces it together from old info about the uncle, who she finds in a clipping like to put his gum on the dashboard like his hero Chuck Yeager.
Brass brings Renata and the Uncle in and busts them for racing each other, killing Cindy, and then returning the car to Trevor's house. (From whence Cindy had stolen it for them.) Renata's about to confess and then her uncle says they're leaving. Brass arrests Cindy and Gus admits it was his fault. He flashes back to Cindy's loss at the rumble and how he got mad at Trevor beating her. She claimed Trevor's car was better. Uncle Gus said it wasn't about that it was about Renata's driving and so they stole the car to prove his point. Except he was wrong, she was beating him in Trevor's car. He lost control of Renata's car and killed Cindy. He told Renata to beat it. He tried to find Cindy but couldn't but he could tell from the impact he couldn't have helped her. He paid Leo to make the car new overnight. Gus says it was on him. Renata tries to claim it was her fault for asking Cindy to steal the car. Brass agrees with them both.
Catherine says the D.A. is going to charge them both as she and Nick walk out. As they pull out of their spots she gives him a look and races him out of the parking garage.