The deceased was identified as 33-year-old Rajeev Rajendran, from Tamil in Sri Lanka.
Manus Provincial Police Commander, Chief Inspector David Yapu, said the deceased was admitted at the hospital and was receiving treatment for self-inflicted wounds when he hung himself between the hours of 2am and 4am on Monday.
He was in hospital after he attempted to kill himself by using a razor blade to cut his throat.
Whilst admitted, he hung himself in the laundry building of the hospital.
A forensic team from Port Moresby attended to the scene and retrieved his body.
The body of the deceased will be flown to Port Moresby for an autopsy.
The late Rajendran also had a pending case before the court at the time of his death.
He was arrested and charged in January this year over the sexual assault of a minor in a hotel in Lorengau.
The case had gone through the committal court process and sufficient evidence was found against him, putting it for trial in the National Court.
He was to appear in the National Court in Lorengau for mention on Monday, the same day his body was discovered.
PPC Yapu said Police have not ruled out foul play and will continue investigations into his death.
(Loop file pic)