"I didn't kill her. I killed the demon inside her," Michael Brea, 31, told the Daily News from a hospital prison ward where he was being held after his arrest on murder and other charges.
"I just kept cutting her. No one could stop me. I was doing the work of God," he told the paper.
Relatives issued a statement Friday expressing their support for Brea, whom they called "a compassionate, gentle, intelligent, spiritual and loving man" in need of help.
"His family and friends know, without question, that Michael was not well in the moments leading to (his mother's) death," the family said.
Yanick Brea, 55, had cuts to her head when she was found Tuesday in the bathroom of her Brooklyn apartment, police said.
Brea, who had small roles in ABC's now-canceled show "Ugly Betty" and the movie "Step Up 3D," was in the bedroom with a 3-foot-long sword, police said.
He told the Daily News he had been living in a private world filled with Masonic symbolism and black magic that led to his act. The day of the attack, he said, a man approached and tried to put a curse on him, and then strangers began speaking to him about his mother as he rode a subway to the apartment he shared with her.
"I felt like Neo from 'The Matrix.' I began hearing voices and feeling powerful. ... It was a sign," Brea said.
In the 1999 movie, Neo -- played by Keanu Reeves -- is a computer hacker who comes to realize that his life is an elaborate illusion controlled by malevolent machines. He joins an underground resistance in battling to experience unvarnished reality.