MORRIS PARK, N.Y. (WABC) -- Police are trying to find out what caused a motorist to crash into a group of trick-or-treaters in the Bronx Saturday, leaving three people dead.Police are examining whether the 52-year-old driver may have suffered a medical emergency such as a seizure. A preliminary investigation showed the car was not speeding at the time of the crash, and no drugs or alcohol were found in his system, police said. Detectives are looking at what kind of medication he had been taking to see if that might have been a factor in the crash.The incident happened just before 7 p.m in the Morris Park section of the Bronx.According to NYPD, the driver of a black 2011 Dodge Charger was heading westbound on Morris Park Avenue when he twice rear-ended a Toyota Camry, which was being driven by an Uber driver. The Charger then continued into oncoming traffic, jumped the curbs, struck the victims and came to a stop in the front year of a house on Morris Park Avenue near Bogart Avenue.The three people killed were:- Nyanna Aquil, 10- Louis Perez, 65 (grandfather of Nyanna)- Kristian Leka, 24All lived in the Bronx.Three others were injured in the crash. Nyanna's younger sister, 3-year-old Yasima, suffered injuries to her neck. She has since been released from the hospital and is recovering at home. A 9-year-old girl and a 21-year-old woman were also hurt in the crash. They were treated and released from the hospital.The driver of the crashed Charger was taken to Jacobi Medical Center in stable condition. Police said he is cooperating with investigators and no charges have been filed.The driver of the Camry, a 57-year-old from the Bronx, was charged with aggravated unlicensed operator for driving with a suspended license.Officials confirmed that some of the victims were trapped under the car, and others went flying. Neighbors thought the severed body parts were just gruesome Halloween props, until they realized that the nightmare was real."I didn't comprehend what I was seeing until I realized what I was seeing. I had to walk away. Too much involved," says resident John del Giudice.New York City Mayor Bill de Blasio issued a statement Sunday about the crash: