Police in suburban Detroit say they'll take a weekend break after digging for the remains of up to seven girls who have been missing for years.

The excavation started Monday in a wooded area in Macomb County, about 30 miles (50 kilometers) northeast of downtown Detroit. No remains have been found, although Warren, Michigan, police Commissioner Bill Dwyer says investigators have discovered "certain items." He didn't elaborate.

Dwyer says he's "totally committed" to solving the cold cases. He cited rain as a reason to suspend digging. State police and the FBI are dropping out of the search.

The search began after police interviewed a man who's in prison for the slaying of a 13-year-old girl. Cindy Zarzycki's remains were found in 2008 near the same wooded area in Macomb Township.