Authorities in Massachusetts have issued a community alert after four people suffered fatal overdoses over the last two days.
Chelsea Police Chief Brian Kyes said Sunday the overdoses have occurred since Friday. Three have happened in the city within the past 24 hours.
Kyes says it appears that there may be a deadly batch of heroin in the area. He says it's possible that the drugs used may have been laced with synthetic opioid fentanyl.
The department said on its website police are actively seeking to find the source through chemical analysis.
Massachusetts State Police assigned to the Suffolk Country District Attorney's office as well as Chelsea Police are investigating.