He was a quiet Texas teenager who danced with his Greek church group and played football. He had a passion for symbology and Japanese history.
On Friday, authorities said, 17-year-old Dimitrios Pagourtzis put on a trenchcoat, walked into an art class at his high school in Santa Fe, near Houston, and shot nine fellow students and a teacher dead.
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There were no red flags beforehand to indicate that Pagourtzis was headed for trouble, Governor Greg Abbott said. But social media and journal entries revealed a young man infatuated with guns, determined to kill and to die.
A Facebook post on April 30 showed a black T-shirt with the words "Born to Kill" printed in white. The Facebook page has since been taken down.
Abbott told reporters that entries in the teen's personal journals, seized by police, showed, "Not only did he want to commit the shooting, but he wanted to commit suicide after the shooting."
But, Mr Abbott said, "He didn't have the courage to commit suicide."
He said the suspected gunman, a junior at Santa Fe High School, was armed with a shotgun and a .38 revolver, both taken from his father, possibly without the parent's knowledge.
Pictures of a Greek festival affiliated with the Assumption of the Virgin Mary Greek Orthodox Church in Galveston showed Pagourtzis, the son of a Greek immigrant, dancing with other costumed performers. The pictures were archived on the church's Facebook page. He was identified in a photo caption.
One fellow student said Pagourtzis was especially fascinated with Japanese imperialism and samurai culture, and interested in mystical and military symbols like the German Iron Cross and hammer and sickle he wore as pins on his clothing.
Classmates remembered that he often wore a trenchcoat, similar to the one authorities said the shooter used to conceal the firearms carried into the school.
One student said Pagourtzis kept to himself and "never really talked to other people". But Clayton George, 16, a sophomore who played football with Pagourtzis this year, said he regularly spoke with him at practice.
"He was one of the nicest guys on the football team. Always easy to talk to," he told Reuters. But, he said, Pagourtzis would sometimes get "poked" by his teammates in locker room horseplay.
Pagourtzis was held without bond on Friday, authorities said, at the Galveston County Jail after being charged with capital murder.