The Latest: Police: Suspect in slayings bragged in prison

Investigators travel across a huge field to a dig site along a rural wooded area in Macomb Township, Mich., Wednesday, May 9, 2018. Authorities were set to resume excavation work in a wooded area northeast of Detroit for the remains of a 12-year-old girl and the bodies of up to six others missing for decades. (Todd McInturf/Detroit News via AP)
Investigators prepare to travel across a huge field to a dig site along a rural wooded area in Macomb Township, Mich., Wednesday, May 9, 2018. Authorities were set to resume excavation work in a wooded area northeast of Detroit for the remains of a 12-year-old girl and the bodies of up to six others missing for decades. (Todd McInturf/Detroit News via AP)
Investigators huddle before they travel across a huge field to a dig site along a rural wooded area in Macomb Township, Mich., Wednesday, May 9, 2018. Authorities were set to resume excavation work in a wooded area northeast of Detroit for the remains of a 12-year-old girl and the bodies of up to six others missing for decades. (Todd McInturf/Detroit News via AP)
In this March 6, 2017 photo released by the Michigan Department of Corrections, Arthur Ream is shown. Police are digging in woods northeast of Detroit near where the body of a 13-year-old girl who went missing in 1986 was found more than a decade ago. In 2008, Ream led police to the area and the remains of Cindy Zarzycki who disappeared. Zarzycki had been dating Ream's son at the time of her disappearance. Arthur Ream was convicted of her murder and is serving life in prison. (Michigan Department of Corrections via AP)

The Latest: Police: Suspect in slayings bragged in prison

Investigators travel across a huge field to a dig site along a rural wooded area in Macomb Township, Mich., Wednesday, May 9, 2018. Authorities were set to resume excavation work in a wooded area northeast of Detroit for the remains of a 12-year-old girl and the bodies of up to six others missing for decades. (Todd McInturf/Detroit News via AP)
Investigators prepare to travel across a huge field to a dig site along a rural wooded area in Macomb Township, Mich., Wednesday, May 9, 2018. Authorities were set to resume excavation work in a wooded area northeast of Detroit for the remains of a 12-year-old girl and the bodies of up to six others missing for decades. (Todd McInturf/Detroit News via AP)
Investigators huddle before they travel across a huge field to a dig site along a rural wooded area in Macomb Township, Mich., Wednesday, May 9, 2018. Authorities were set to resume excavation work in a wooded area northeast of Detroit for the remains of a 12-year-old girl and the bodies of up to six others missing for decades. (Todd McInturf/Detroit News via AP)
In this March 6, 2017 photo released by the Michigan Department of Corrections, Arthur Ream is shown. Police are digging in woods northeast of Detroit near where the body of a 13-year-old girl who went missing in 1986 was found more than a decade ago. In 2008, Ream led police to the area and the remains of Cindy Zarzycki who disappeared. Zarzycki had been dating Ream's son at the time of her disappearance. Arthur Ream was convicted of her murder and is serving life in prison. (Michigan Department of Corrections via AP)