A 12-year-old girl who was shot at by the suspect as she fled the home alerted police at a nearby gas station, authorities said.
The fourth victim was a 19-year-old woman identified by family members as the alleged gunman's wife, Twanda Thompson, who he married just weeks ago and who was expecting their second child. She and Jihad were found in bed in a separate bedroom with gunshot wounds to their heads, police said.
The two wounded were identified by family members as the alleged gunman's mother, Leona Larry, and his 13-year-old nephew, Demond Larry. They both suffered gunshots to the head and were taken in critical condition to Advocate Christ Hospital in Oak Lawn, a fire department spokesman said.
The suspect was arrested several miles away about an hour and a half after the shootings.
A law enforcement source, citing preliminary information, said the man told police he had been hearing voices that told him to bring his family to Allah. He also told police he didn't have enough ammunition, the source said.
The suspect had been arrested in Madison last fall for allegedly beating Thompson, according to records. Just last week, Thompson filed a paternity case against the suspect, records show.
And in recent days, the suspect had been arguing with his wife because he wanted her to dress in Muslim garb and she refused, according to Shirina Thompson, the older sister of Twanda Thompson.
The suspect had become a Muslim while in federal prison on a gun charge, relatives said. Recently, he had been acting strangely, talking about "going to Allah," Thompson said.
Twanda had been with the suspect two years, but they had been married for the last two to three weeks, said Shirina Thompson. Tawanda was pregnant with a girl she was going to name Khadijah, she said.
On Tuesday, the suspect had come down from Madison, Wis. with his wife and son and mother to visit his sister, Keisha Larry, according to the suspect's sister, Letisha Larry, 30. "He snapped out and killed them," Larry said. "He was saying some Muslim stuff."
Larry, who also lives in Madison, said her brother had been a "little weird" lately.
"He was like just saying little weird little stuff about (how) he was an angel and we were demons, there's demons in the house," Larry said.
The suspect carried around the Quran, and about a week ago he started telling his family that something in the book told him to kill someone, Letisha Larry said.
She wasn't aware of her brother having any diagnosed mental problems, and she said she thinks he should be brought to justice.
"How you going to shoot your mom and then your wife and kids? That's just crazy," Letisha Larry said. "Your niece and nephew. Why would you do something like that? You were just a killer."
Thompson and her mother Veronica said they were told by police that the suspect opened fire unprovoked, first shooting his wife in the neck and wounding the others in the head. When he saw that his wife was still alive, he shot her in the head, Thompson said.
Police were alerted around 4:25 a.m. today after a 12-year-old girl ran out of the brick house in the 7200 block of South Mozart Drive and down the street, sources said.