PHILADELPHIA — Police say a black doll was found hanging from a noose above a playground that partly sits on top of a burial site for 5,000 black Philadelphia residents.

The doll was discovered Thursday morning.

Mayor Jim Kenney called it a “despicable act” and said the city will do everything it can to bring to justice those responsible.

The city had recently announced plans to put up a memorial to those buried beneath the playground.

The 19th-century burial ground was established by Richard Allen, a freed slave who founded the African Methodist Episcopal Church. Its existence had been forgotten until a historian began researching the site about a decade ago.