FBI and Philadelphia police personnel began digging around the home on the 400 block of Chew Avenue last week. The work included removing a backyard shed and searching the soil, where the bones were found. Investigators were more than halfway through the backyard excavation as of Monday, sources said, and plan to move to the front yard when that work is finished.

The home is being investigated in connection with Raymond “R.C.” Horsch, a suspected serial killer who died last year. At least seven missing women have been linked to the property; five are feared dead.

Investigators also used luminol, a chemical that can reveal potential traces of blood. The test showed human DNA in several locations around the home, sources said. Those findings require further testing, and authorities have not publicly identified whose DNA it is.

The investigation began this summer after Horsch’s son, Eugene, was arrested in Center City following a traffic stop. Authorities said he had guns, drugs and false law enforcement credentials, and was with a woman carrying identification belonging to Blair Tonzelli, who has been missing since 2023.

That woman later told investigators she was afraid of the home’s basement and said “bad things happened in that basement to other people,” according to sources cited in reports on the case.

Investigators have also removed drums containing an oily, sludge-like substance from the property and examined the home for possible evidence of wet cremation, a chemical process used to break down human remains. Previous work included removing two clogged sewer laterals connecting the house to the street’s main sewer line.

The animal-bone finding does not resolve the questions surrounding the missing women. Investigators have not announced when excavation or additional DNA testing will be complete.