DETROIT (AP) — A man suspected in the December slaying of a Detroit police sergeant's wife has told investigators he is responsible for at least seven contract killings in less than two years.

Vincent Smothers, 27, has been charged with two counts each of first-degree and felony murder and one count each of assault with intent to murder, being a felon in possession of a firearm and possessing a firearm during a felony.

Two people died and a third was wounded in the June 2007 drug-related shooting. Conviction on the murder charges would carry an automatic penalty of life in prison without parole.

Smothers was arraigned Monday afternoon in Detroit's 36th District Court, where Magistrate Sidney Barthwell Jr. entered a not guilty plea on his behalf.

Barthwell called Smothers "an extreme danger to the community" and ordered him jailed without bond until his preliminary examination May 1.

Following his arrest Saturday in Shelby Township, about 20 miles north of Detroit, Smothers told Detroit homicide investigators about four other cases, including the Dec. 26 shooting death of Rose Cobb, 47, outside an east side pharmacy, Police Chief Ella Bully-Cummings said Monday during a news conference.

"He made a living by murder for hire. He was, in plain terms, a hit man," Bully-Cummings said.

Bully-Cummings called Cobb's slaying the day after Christmas an "ambush."

Her husband, Sgt. David Cobb, had driven the couple to the CVS and was inside the pharmacy when she was shot while sitting in their van.

David Cobb was arrested about 6:30 a.m. Sunday at the couple's east side home. No details about his arrest were released by Bully-Cummings. Cobb is expected to be arraigned Tuesday, court officials said.

Investigators have three other suspects who could be charged for their roles in the seven slayings.

"Warrants have been prepared by homicide," Bully-Cummings said. "They are being submitted to the prosecutor's office on every one of the shootings we are aware of and on every one of the individuals that are being implicated as being involved in these homicides."

The Wayne County prosecutor's office said it didn't know if Smothers or David Cobb had retained attorneys, and there was no listing for either man in Detroit.