A man who killed two women and two children in Connecticut is expected to be a key witness against another man who authorities say killed seven people in the state in 2003.

Court documents filed last week allege William Devin Howell told cellmate Jonathan Mills about the seven killings. Mills is serving life in prison for four killings in Guilford in 2000.

Mills' testimony is expected to be key in a court hearing next week on whether there's enough evidence to take Howell to trial. Mills also may get all or part of a $150,000 reward in Howell's case.

Howell, a Hampton, Virginia, native, is serving time for one slaying and has pleaded not guilty to the other six. All seven victims were found buried in New Britain.