The man who claims to have firsthand knowledge in the murder of Grosse Pointe Park mother Jane Bashara spent the night in jail.

Sources told the Local 4 Defenders the man, who they are calling Joe, walked into the Grosse Pointe Park Police Department at about 4 a.m. Tuesday.  He then told police he was paid to help in the murder of Bashara and that there was a second person involved in the crime, sources said.

Special coverage: Grosse Pointe Park murder investigation

Sources said Joe also told police Bashara was viciously attacked and killed in her own garage, and he witnessed it.

Her body was then taken in the backseat of her Mercedes-Benz SUV, driven to Detroit and abandoned, sources said. Joe told police he placed Jane's lifeless body in the SUV.

The identity of the second person involved is not yet known as police work to verify the information provided by Joe.

Joe told police that he worked for Bob Bashara doing odd jobs around his rental properties.

Joe is being held by police but he has not been charged. Sources say he left a leather jacket and two cellphones with his friend. When the friend noticed scratches on the jacket, he decided to hand the items over to police, sources say.

The 56-year-old woman was found dead in the back of her SUV Wednesday morning in an alley in Detroit.

An autopsy showed Bashara's windpipe had been crushed.

Jane Bashara’s husband, Bob Bashara, had been pegged a person of interest by police. Sources said he failed a polygraph, but he has not been charged.

Sources said police don't think whoever killed Jane Bashara acted alone. Sources tell Local 4 that an accomplice helped stage the crime scene as a robbery gone wrong.

Bob Bashara reported his wife missing the night before she was found dead. During an interview with Local 4, he said he thought she was out running an errand when he got home Tuesday night. But when she didn’t answer her cell phone several hours later, he got worried.

Investigators have been to the couple’s home, taking computers and other items from the house. A K-9 has also scoured the home.

Her funeral was Tuesday.

Full story:Hundreds attend Jane Bashara's funeral