Arusha Regional Police Commander, Basilio Matei confirmed the death, adding that investigations are underway to establish the circumstances which led to the demise of the ICTR staff.
"We're investigating the cause of the death," he told Hirondelle Agency.
He said a postmortem exam would be conducted in presence of the deceased's relatives and High Commission officials, who have already arrived in Arusha.
However, he said that police found alcohol bottles and what looked liked drugs in the deceased's seating-room, where he had invited two friends the previous night [Tuesday].
According to the evidence of the deceased's watchman, the drinking spree started from around 8pm up to just before midnight when the two guests, looking drunk, left the house.
He said the decease's watchman had initially refused to open the gate for the unidentified visitors, but the late Rajapaksa ordered they be let in. The watchman told police that it was his first time to see the two visitors. Policemen are tracing the two visitors.
The late Rajapaksa was found face-down on the floor with blood oozing from his mouth and nose, added Matei. The first person to discover the death was the deceased's house-girl on Wednesday morning, who alerted the police.
The late Rajapaksa's contributions included prosecution of four former Rwandan top ministers in a trial known as "Government II''.
He was earlier this year moved to the Appeals Section of the ICTR.
The deceased had his school education at Royal College Colombo and later qualified as Barrister in London. His working stint included an attachment to the Sri Lankan Attorney General's Department as State Counsel. He was the only son of the late George Rajapaksa, a prominent Sri Lankan politician.
© Hirondelle News Agency