BANGOR – An inmate at the Penobscot County Jail was found dead in an observation cell early Tuesday morning less than 18 hours after another prisoner hanged himself at the facility.

Bruce Hansen, 42, was discovered dead at 6:45 a.m. by jail officials, Penobscot County Sheriff Glenn Ross said Tuesday. The man appeared to have died of natural causes related to alcoholism, Ross said.

The man’s body was taken to Augusta, where an autopsy was to be preformed by the State Medical Examiner’s Office. Family members in Milo were notified of Hansen’s death Tuesday afternoon, said Ross.

Described by law enforcement officials as a transient, Hansen was arrested by Bangor police Saturday on an outstanding warrant for criminal trespass. Unable to pay the $10 bail fee, Hansen remained in jail.

Hansen was intoxicated, according to Ross, when he was brought into the jail and kept in a special observation room while he went through the detoxification process. The inmate was under the care of the jail’s medical staff.

A registered nurse is at the jail daily between 8:30 a.m. and 9 p.m. and on call overnight, according to Cheryl Gallant, jail administrator.

Guards monitored Hansen every 15 minutes, the sheriff said, but thought he had been sleeping until they determined that he wasn’t breathing. Ross said the log showed Hansen had been checked every 15 minutes, but the interaction that occurred during the checks is under investigation.

“In our business there’s always a risk of something like this happening because of the population we deal with on a day-to-day basis,” Ross said late Tuesday afternoon. “It’s unfortunate that we’ve had these deaths, but they are unrelated to each other.

“One of our great concerns is the fact that people in medical and psychiatric crises are being sent to county jails when they first should be sent to mental health or medical facilities,” he said. “We’re a default agency. … Every jail in Maine continues to face this same risk on a day-to-day basis.”

Ross told the county commissioners at a meeting Tuesday morning that Detective Robert Jordan of the sheriff’s office and Detective David Preble of the Maine State Police are investigating Hansen’s death. John Hinkley of the Maine Department of Corrections also is examining procedures followed by jail staff to determine if they were followed properly.

The sheriff said the results of the autopsy and the investigations into the two deaths would be completed in a few days.

Hansen’s body was discovered a few hours before Ross was sworn in as sheriff and less than a day after an Argyle man hanged himself with a bedsheet.

Gardner Whalen, 37, died shortly before noon Monday and only minutes after a guard checked his cell, according to Ross. The man had turned himself in Sunday night to serve a 60-day sentence after his conviction for night hunting and possession of a firearm by a felon, Ross said Monday.

Whalen was arrested last fall after shots were reported being fired in the area of Mann Hill Road and Eastern Avenue in Holden, according to Sgt. Troy Morton of the sheriff’s office. Whalen fled into the woods in the early morning hours but turned himself in later that morning.

Whalen’s apparent suicide was the sixth at Maine jails this year.