Nassau police are trying to track down a brazen thief who walked into a pediatrician's office in East Meadow this morning, grabbed his keys and took off with the doctor's car. Dr. John Zaso says surveillance cameras in and around his Merrick Avenue office captured the crime on video. Normally, patients are buzzed in and out for security, but the suspect slipped in when patients were leaving, he says. Surveillance video shows the suspect grabbing Zaso's keys and then leaving in his black Jeep SUV. Zaso says his car is a state-certified emergency vehicle with red lights, sirens, a defibrillator and even a police radio. "They have this car now on the road, with red lights and sirens that can be misconstrued as a police vehicle and people have to be careful," Zaso says. The doctor says he's unsure what the suspect was after, but noted his office doesn't keep narcotics or prescription pads. His car has medical doctor plates, he says. Police say they're collecting fingerprints and reviewing the surveillance video. The suspect is described as a black male, about 5 feet 10 inches tall, in his late 30s to early 40s. He was wearing a black leather jacket, a black cap and jeans, police say.