A rash of heroin overdoses in Philadelphia killed six and sent others to the hospital Sunday, police said.

Detectives in the city's East Detective Division reported investigating the overdose deaths. Investigators there did not know the number of people who overdosed and survived, but said there were several.

The deaths, first reported by 6 ABC news, were at the following locations, according to police: a 24-year-old man on the 3000 block of North Broad Street; a 42-year-old man on the 3300 block of Kensington Avenue; a man in his 30s on the 600 block of East Indiana Avenue; a woman in her 30s on the 3300 block of Amber Street; a man in his 40s on the 2800 block of D Street; a man in his 40s on the 3300 block of Kensington Avenue.

Exactly what caused the deaths is still under investigation. It could be a bad batch of the drug circulating, or several bad batches, detectives said. Often a cluster of overdoses can happen when heroin is laced with a toxic substance like fentanyl.

District Attorney Seth Williams says the death toll could have been higher had police not been equipped with the heroin overdose antidote Narcan.

Jason Laughlin