A Miami skateboarder who fractured his skull when he slammed into a garage's concrete wall could face criminal charges for claiming a group of black men assaulted him, police said today. Rene Betancourt, 22, told police that on July 7 he was attacked by a group of men while skateboarding in downtown Miami. According to the police report, he claimed the assault took place during an attempted robbery. But surveillance video from a nearby office building released on Friday shows Betancourt skate boarding in the garage and plunging face first into a concrete wall of the garage. The impact left him unconscious and lying on the ground for nearly five minutes. After waking up, Betancourt stands up in a daze and stumbles into the garage's elevator. Betancourt's family found him slumped in his car, bloodied and bruised. After rushing him to a hospital, doctors determined he had a fractured skull, fractured orbital bone, with blood clots and lacerations in his head. "All we had from the beginning was three to four black males," says Napier Velazquez of the Miami Police Department. "As the police department, we gather info on the scene, so we assume that all the information is valuable. We don't question where they [the victims] get their information from." But the video, he said, "changed the entire investigation."