Man calls 911 to confess he killed wife and 4 children, 25 years after killing ex-wife

When police responded to a Detroit-area home on Wednesday morning, they found a horrific scene. Four young people ranging from ages 4 to 19 were dead, police confirmed. The two older victims identified as Kara Allen and Chadney Allen had been shot execution style. Kaleigh and Koi Green, ages 4 and 5, had been asphyxiated in a car using exhaust from a hose hooked up to the tailpipe and routed into the car. Then, police say, the girls' bodies had been moved into their beds. Also at the scene, a woman had been shot and stabbed; she was rushed to the hospital in critical condition. She was later upgraded to stable condition.
Police arrested Gregory V. Green, a 49-year-old man who had spent time in prison before – for the 1991 stabbing death of his pregnant wife. Back then, he had pleaded no contest to second-degree murder. Court records obtained by PEOPLE indicate that Green was released from prison in 2008.
In Wednesday's incident, the two young girls were Green's daughters with Faith Green, his current wife, the only victim to survive. The two older teens were Faith Green's children from a previous relationship. According to court records obtained by PEOPLE, Faith Green had filed for divorce last month after six years of marriage. The petition cited a "breakdown in the marriage relationship."
Police say they first learned about the killings after a 911 call – from Gregory Green. "The call was made by the suspect himself," Captain Michael Petri told reporters in a press conference. "All of this seemed to have stemmed from a domestic violence-related incident."
In a statement to ABC News, Mayor Dan Paletko called the killings "a tragedy in every sense of the word."
Green is currently being held at the Dearborn Heights Police Department. He has not yet entered a plea and it was not immediately clear if he's retained an attorney