Death of Nikolas Cruz Adoptive Mother Might Have Been Breaking Point

The death of his adoptive mother in November might have been the breaking point for confessed Florida school gunman Nikolas Cruz.

Less than three months after her death, Cruz killed 17 people at Marjory Stoneman Douglas High School on Wednesday.

Cruz and his biological brother, Zachary, were adopted by Roger and Lynda Cruz, who were from Long Island, New York. They moved to Florida, where they adopted the boys, an aunt, Barbara Kumbatovich told Newsday. Roger Cruz died in 2004.

Cruz grew up close to his mother, although he developed emotional issues before her sudden death. Neighbors said Cruz's mother often called police. According to CNN, police were called to their home 39 times since 2010. Others said he killed animals, and acted out.

Lynda died on Nov. 1, after getting the flu and battling pneumonia.

After her death, Cruz lived with a friend's family at the time of the shooting. He moved in with the friend's family around Thanksgiving, and had already owned the AR-15-style rifle he used in the shooting.

"Lynda was very close to them," Kumbatovic told the Washington Post. "She put a lot of time and effort into those boys, trying to give them a good life and upbringing."

"She devoted a lot to their activities," Kumbatovic told Newsday. "She had concerns that they weren't getting the right treatment. The younger son seemed to adjust better."

Kumbatovic, who was the sister of Cruz's father, also thought Lynda's death might have triggered her nephew.

"Kids — I don't think they realize the impact of death until after it happens," she said.

Law enforcement sources also told ABC News that Cruz told investigators he heard the voices of "demons" in his head, who gave him instructions. The attorney representing the family Cruz lived with at the time of the shooting described him as "depressed" after Lynda's death.

"Lynda dealt with it like most parents did. She was probably too good to him," Kumbatovic told the Post. "She made a beautiful home for them. She put a lot of effort and time into their schooling, their recreation, whatever they needed. . . . She went over and above, because she needed to compensate for being a single parent."

Cruz confessed to killing 14 students and three teachers at his former high school. He was expelled last year after reportedly getting into a fight with his ex-girlfriend's new boyfriend. He has been charged with 17 counts of premeditated murder.