Three people are dead and four were hospitalized after a "party or event" on the south side of Pittsburgh, according to police.
Police Director Wendell Hissrich confirmed the deaths and hospitalizations on Sunday morning.
Police are looking for a party or event which may have distributed orange paper wrist bands. All seven victims were wearing orange paper wrist bands when they were found by police, according to a police report. The deaths and hospitalizations are being considered a drug-related overdose, according to press release.
Police said the seven victims had been at a venue together and then went to an apartment where "they apparently overdosed on drugs. The victims all took the narcotics at the same time and in the same location," police said in a statement.
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Five victims were found in one apartment and another victim was found in an elevator outside the apartment.
An additional victim was located on the street. All of the victims are men, according to local news station WPIX, and a man called 911 at approximately 2 a.m. for help.
Three of the four men who were hospitalized are in stable condition, police said. One is in critical condition.
Police clarified later on Sunday that they believed the drugs were not passed around at a venue, which would have affected more people, but instead was isolated to the men in the apartment. Authorities said people who attended venues with orange wrist bands are not a health risk.
However, police said they fear there could be a tainted and possibly deadly batch of drugs in the community.
"We remind the public not to use drugs. Simply put: You do not know what's in that drug," officials said in a statement.
Pittsburgh Police did not immediately respond to a request for comment made by NBC News.
Pittsburgh police said they are investigating the deaths and asked for anyone with information to contact them at (412) 323-7141.