As more information surfaces about the man suspected of killing 17 people in a mass shooting at a Florida high school earlier this month, a pattern of traumatic personal issues and missed warning signs continues to grow.

According to the New York Post, 19-year-old Nikolas Cruz’s life was often in upheaval dating back to at least the age of 5, when he witnessed his father’s death from a heart attack.

His mother, Lynda, recalled that he came into the kitchen crying, to which she asked if his father had punished him.

“Nope,” he reportedly said. “Daddy’s dead.”

In the years since, Cruz, who had already been diagnosed as developmentally delayed, was subjected to bullying by his younger brother and schoolmates, as reported by the Sun Sentinel.

Following the massacre at Marjory Stoneman Douglas High School, 18-year-old Zachary Cruz reportedly told authorities that he “wishes he had been ‘nicer’ to his brother,” acknowledging that he and his friends had treated the troubled child cruelly.

Nikolas Cruz also displayed disturbing outward signs, according to those around him.

Last year, as a junior at the same school he returned to with a rifle on Feb. 14, he reportedly pulled out a dead bird during a class and held it to his crotch.

“I saw some feathers and I knew it was a bird,” said classmate Tyra Hemans. “That was disturbing.”

She said she did not look at the distressing display and did not report it because it was not her business.

According to Hemans, one of the friends she confided in about that incident was Meadow Pollack, who died in the mass shooting.

“We kept it to ourselves,” she said.

Federal investigators reportedly received a tip indicating Cruz also took a dead bird into his home, where he dissected it in the kitchen to determine what was inside.

Additional details indicate the number of casualties could have exceeded the 33 individuals shot in the rampage.

Reinforced glass meant to withstand the pressures of a hurricane reportedly protected a group of students hiding in the school’s courtyard when the gunman took aim at them from a room on the third floor.

[Featured image: Nikolas Cruz/Broward County Jail]