The Texas teen who killed 10 people at his school last week studied other mass shootings before the slaughter, a new report says.

Dimitrios Pagourtzis, 17, meticulously researched tactics used by gunmen in other mass shootings, ABC News reported, citing sources.

“He studied previous mass shootings and used aspects of those [attacks] in his own shooting,” the outlet quoted a source as saying.

Pagourtzis fatally shot eight students and two teachers and wounded 13 others inside Santa Fe High School, according to officials.

He surrendered to police, and has been charged with capital murder.