Officers say a sniper who killed himself after firing on cars and injuring people on a Georgia highway idolized the Parkland, Florida, school-shooting suspect. A sheriff says 26-year-old landscaper Rex Whitmire Harbour fired at least 17 times and hit at least seven vehicles traveling northbound on Georgia 365 outside Atlanta.

Two people were wounded and a third was hurt by broken glass. None of their injuries was life-threatening.

Authorities believe Harbour was firing at random and wasn’t targeting anyone. A search of Harbour’s Snellville home, where he lived with his parents, turned up “hate-filled” handwritten documents, officials say.

Harbour’s mother told investigators her son was mild-mannered and quiet. But the writings suggest he viewed Parkland, Florida, school shooter Nikolas Cruz as a “hero” who gave him “courage and confidence,” said Hall County Sheriff Gerald Couch.

Couch said the writings indicated Harbour “idolized” Cruz, who killed 17 at Marjory Stoneman Douglas High School in February.

Couch told a news conference a deputy chased after a suspicious car pulling out of a wooded area adjacent to the highway. He said the suspect shot himself in the head, and his car rolled to a stop. Harbour later died at Grady Memorial Hospital.

Couch said investigators found three 9mm handguns, a 12-gauge shotgun, a BB-gun and more than 3,400 rounds of ammunition inside his vehicle. Deputies found 17 shell casings from Harbour’s nine millimeter just off of Highway 365.

Crime-scene investigators also found a trail camera in nearby woods, possibly set up by a hunter, that captured Harbour as he was walking toward the area where he allegedly took a position to open fire at the drivers.

A 72-year-old man was reportedly shot in the hip and a 54-year-old man was shot in the leg. Both men were transported for treatment and are expected to recover.