Indianapolis police are investigating the death of a man found dead in a tanning bed at a Planet Fitness gym Monday morning.

The Marion County Coroner’s Office identified the man as Derek Sink, 39.  

Sink went into a tanning bed Friday, his family told NBC affiliate WTHR of Indianapolis. 

When he failed to come home, they reported him missing. His aunt said Sink was wearing an ankle monitor, which led investigators to determine he never left the gym. He was ultimately located in the tanning bed at the gym, in the 8000 block of Hardegan Street, on Monday morning. 

Relatives said that Sink had struggled with drugs and that a needle was found in the room with him. 

Marion County Superior Court records show Sink was charged with possession of a narcotic drug and possession of a controlled substance last year. In a plea agreement on the first charge, he was sentenced to one year of home detention, including drug testing, which started in May.

It was not clear how he went unnoticed for so long.

The coroner’s office had not determined a cause or manner of death as of Wednesday morning.  Indianapolis police said the death investigation continues.

Elizabeth Len was at that Planet Fitness on Monday morning before law enforcement discovered Sink.

She said she and other members noticed a bad smell in the building near the tanning rooms. “The tanning bed has a door, I believe, but still, why are we not concerned that the tanning bed has been closed for three days, potentially?” Len said to WTHR.

Planet Fitness’ Chief Corporate Affairs Officer McCall Gosselin said in a statement: “We were deeply saddened by the passing of one of our members, and the franchise owner is working with the local authorities in their investigation.”

“At Planet Fitness, we have robust operational brand protocols in place, as the safety and well-being of our members is our top priority. We are working closely with our local franchisee to ensure they are upholding those brand protocols,” Gosselin added.