DETROIT – Four people were hit by a pickup truck Thursday at a Tesla popup event outside Shinola headquarters in Detroit.

Witnesses said the truck went flying down Canfield Avenue, where people were looking at Tesla cars for an event. They said the truck, at a high speed, crossed the center line and slammed into four people.

Multiple witnesses told police the truck crossed the line intentionally to hit the victims. Detroit police said alcohol is believed to be a factor, and the 42-year-old driver is in custody. Terrorism is not a factor in the crash, police said Thursday evening.

Witnesses said three people were hit by the truck and flew into the air, including a 73-year-old man who became wedged beneath an Airstream. The 73-year-old suffered a serious head injury in the crash. Two women were also taken to the hospital and are in temporary serious condition.

A fourth person who was injured declined medical treatment and appears to be OK.

Reports from the scene say alcohol may have been a factor. The 42-year-old driver is in custody at Detroit Receiving Hospital where he'll undergo a blood draw.

Detroit police and Wayne State police are at the scene investigating.

Shinola, a high-end watch and bicycle manufacturer, is located in Detroit's Midtown neighborhood next to Traffic Jam & Snug, Third Man Records and Jolly Pumpkin.

Tesla was holding a "Tesla Explores" event outside of Shinola. The automaker is traveling across North America with a mobile gallery pulled by a Model X SUV. The trailer was retrofitted to showcase interior and exterior vehicle options.

A Tesla rep at the popup said the trailer was open for tours after the crash.