The 19-year-old who was charged with the worst school shooting since the Sandy Hook massacre may have snapped after his mother, his last remaining parent, died from the flu in November, according to reports, but all signs pointed to him being an awful person long before that. Nicholas Cruz is accused of gunning down 17 people and injuring 15 others after opening fire with an AR-15 inside Marjory Stoneman Douglas High School in Parkland, Fla., on Wednesday.

He was raised by Roger and Lynda Cruz, but Roger died from a heart attack about 10 years ago, leaving Lynda alone to raise Nikolas and his younger brother Zachary. Lynda, who was 68 when she passed, died Nov. 1 from complications from the flu and pneumonina, according to multiple media reports.

“Lynda was very close to them,” said her sister-in-law, Barbara Kumbatovic, in an interview with the Washington Post. “She put a lot of time and effort into those boys, trying to give them a good life and upbringing.”

There were troubling signs in Nikolas’ youth, Kumbatovic said, noting that he once sicced a dog on a pig his neighbor owned. Nikolas reportedly was very introverted, and would pick fights with other kids, steal mail, throw rocks, and even peek into someone else’s bedroom window, according to the report which quoted interviews with people who knew him.

“Lynda dealt with it like most parents did. She was probably too good to him,” said Kumbatovic, according to 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.”