Paulette Wallace said it wasn't the first time this kind of thing had happened. Her son, she said, has a history of bipolar disorder and schizophrenia.
"He takes the phone willy-nilly, and he'll go, 'Oh, they've got the three men who did whatever . . . Oh, get that one over there, go over there,' like he's really Homeland Security," she said.
New York police confirmed that Donald Wallace has a criminal record in Pennsylvania, Georgia and Virginia with charges that include making terroristic threats, criminal possession of a weapon and assault.
Wallace said that her son would often believe someone was following him or that he was in harm's way, and would call the police and fire departments. In the past year, she said, his episodes grew more severe following a recent decision to stop taking his medication.
She said that she had been preparing to discuss sending Donald to a mental-health center before his "traumatic" episode Tuesday. He had spent time in such facilities in the past, she said.
She said her son began to show signs of mental illness in 1997 when his 8-month-old son, Dyson, died of sudden infant death syndrome while Donald was attending the University of Pittsburgh. He earned a bachelor's degree from Pitt's department of health, physical and recreation education.
Later that year, she said, Donald's father died of leukemia.
Still, she said, Donald went on to earn a master's degree in physical therapy at the University of North Georgia.
Paulette Wallace said that her son is a kind of "genius" and had an affinity for helping people. She and neighbors described him as a "good guy."
"He was helpful to me, a senior," said Candace Thomas, 73. "A couple times I was putting my trash out and . . . he ran over to help me with my grocery stuff and I never had any problems with him."
But neighbors also said he would walk down the street in strange, costume-like clothing, often talking to himself.
"I haven't had any sleep, needless to say," Paulette Wallace said. "It's very difficult being a parent and getting this kind of news on TV about a child that you know better than anybody."