Danielle Blodgett remembers her brother, Michael Olson's jokes the most.
She says he moved to the Valley six years ago for a fresh start, but his life was cut short Friday night.
Phoenix police say Olson was killed off Interstate 10 and 51st Avenue when he was hit by a semi-truck , but the driver just kept on going.
"I think this was a complete accident. I truly believe that," Blodgett said. "My problem is, you didn't stop."
Detectives on the case hope a new piece of evidence will lead them to find the driver.
Surveillance video from a nearby QuikTrip shows several trucks driving through 51st Avenue, but police say they believe a tanker truck that zooms by is the truck linked to the hit and run.
"That driver needs to come forward, and just say that he's sorry to our family," Blodgett said. Detectives, however, say that person could face felony charges if they hit Olson and knowingly left the scene.
"You are a professional; a professional driver knows what he did."