BEMIDJI, Minn. - One man is dead and three others are hospitalized after a series of heroin overdoses in Beltrami County.

Authorities responded to separate calls over the weekend regarding people who had overdosed on heroin. One call regarding a man who wasn't breathing at an apartment complex on the 600 block of Patriot Drive Northwest came in at 5:30 a.m. on Saturday.

Authorities arrived on scene and began life-saving efforts but the man was pronounced dead.

He has been identified as 39-year-old Adrian Richard Dunn, of Bemidji.

The other overdose cases were medical calls -- which the Beltrami County Sheriff's Office and the Bemidji Police Department say they do not comment on.

Authorities are investigating the incidents to see if they're related and to determine where the heroin came from -- they say a chemical analysis of the drug will be conducted to find out if the overdose was caused by the user or if it was a more pure form of the drug.

They say those results will take some time.

Officials continue to interview witnesses on these cases. If anyone has information about the distribution of heroin in the area, they are asked to contact law enforcement at 318-333-9111.