On Friday, May 25, 61-year-old Greg Porter allegedly drove his Mazda SUV onto a crowded sidewalk near Portland State University (PSU), sending three women to the hospital with serious injuries before driving away from the scene. Porter was arrested within a few hours near Northeast 16th and Glisan, and is currently being held at Multnomah County Jail.

It’s still unknown what motivated Porter to drive onto the sidewalk near Southwest 6th and Montgomery.

Court documents released Tuesday show Porter is homeless, unemployed, and living on monthly Social Security checks for an unidentified disability. He enrolled in an alcohol treatment program in 1996, but told investigators he now only drinks once a year. Porter also claims to smoke cannabis daily to manage pain—but hadn't smoked two days prior to his arrest.

Porter has been charged with three counts each of attempted murder, assault in the first degree, reckless driving, and failure to perform the duties of a driver—a charge specifically meant to address hit-and-run drivers.

Christopher Bond, who witnessed the incident, says Porter’s Mazda was traveling at an estimated 35 to 45 miles per hour when he struck the victims. Bond said he believed Porter intentionally drove into the women, but Portland police have yet to confirm a motive.

All three victims were taken to Oregon Health and Science University after the accident—two of them in life-threatening condition and one in serious condition. As of Tuesday, one patient’s condition had been upgraded to “fair,” while the other victims asked their condition not be shared. Only one of the victims, Hannah Cline, has been identified. Cline is a freshman at PSU.

The Oregonian reports that Porter was recently a physical therapy patient at Secora, a physical rehabilitation facility. James Aldred, a Secora administrator, said Porter suffers from delusions. “It doesn’t surprise me that he was involved in something,” Aldred told the Oregonian.