Authorities in Massachusetts are investigating after four people in Chelsea suffered fatal overdoses over two days.
Chelsea Police Chief Brian Kyes said Sunday the overdoses had occurred since Friday. Three happened in the city within 24 hours.
Kyes said it appears that there may be a deadly batch of heroin in the area. He said it's possible that the drugs used may have been laced with the synthetic opioid fentanyl.
In a community alert, the department said police are actively seeking to find the source through chemical analysis.
"The police are here to assist anyone who wishes to seek help without consequences or judgment," the department added.
Massachusetts State Police and local police are investigating.
With reporting by the WBUR Newsroom