Authorities investigating the discovery of more than a dozen chunks of human flesh and body parts in a suburban Detroit sewer have released photos of tattoos featured on some of them.

Sterling Heights police Lt. Luke Riley says the Macomb County medical examiner's office has been studying the small pieces found by contractors clearing debris from the 9-foot, 6-inch-wide pipe Wednesday morning.

On Thursday, the department released photos of some of the pieces, which are marked with what appears to be part of a tattoo. Police have not said if the parts came from one or more people and have given no hint as to the gender or identity of the body or bodies.

Investigators say they don't believe the parts had been in the sewer very long.