GAINESVILLE, Ga. (AP) — 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 said Saturday.

A sheriff says 26-year-old landscaper Rex Whitmire Harbour of Snellville, fired at least 17 times and hit at least seven vehicles traveling northbound on Georgia 365 outside Atlanta around noon on Friday. Two people were wounded and a third was hurt by broken glass. None of their injuries were life-threatening.

Hall County Sheriff Gerald Couch told a news conference that a deputy chased after a suspicious car pulling out of a wooded area adjacent the highway on Friday. 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. Then they searched Harbour's home, where he lived with his parents, and found "hate-filled" handwritten documents.

WSB-TV Atlanta reported that the sheriff said Harbour's mother told investigators her son was mild-mannered and quiet. But the writings suggest he viewed Florida suspect Nikolas Cruz as a "hero" who gave him "courage and confidence," the sheriff said.

"What his motivation was other than just hate, we don't know at this time," Couch said. State investigators and the FBI turned up no criminal history. "He had the weapons, the ammunition and obviously the will to inflict a lot of harm and a lot of hate."