A man sleeping in a Medford, Massachusetts, business that caught fire overnight has died, officials said Sunday.

Authorities responded to a report of a fire on Mystic Avenue around 4:20 a.m. and located the fire in a commercial building on 50 Swan St.

According to authorities, someone who arrived on scene had knowledge that an employee had been sleeping inside the business.

The man was located in the bathroom and firefighters began lifesaving measures, according to police. The man was taken to Massachusetts General Hospital, where he later died from his injuries. His name has not yet been released.

The cause of the fire is still unknown. The incident is under investigation.