The State Medical Examiner has concluded that a man who died at Cumberland County Jail last week died of a heart attack.

Authorities say Mark Kemberling, 46, of Brunswick died Wednesday of heart failure stemming from hypertensive heart disease.

Kemberling was serving a seven-day sentence for driving with a suspended license. Jail workers called Portland rescue at 8 a.m. reporting that an inmate was in medical distress. He was taken to Maine Medical Center where he was pronounced dead that morning.

The Portland Police department was asked to look into the case because the man was in county custody at the time of his death.

The state Medical Examiner performed an autopsy and determined the death was due to natural causes.