Mr Fungavaka suffered severe head injuries that same night and was rushed to hospital.
He died six days later.
Six men, including five Tongan police officers, were charged with Mr Fungavaka's manslaughter.
Another officer, Constable Fatai Faletau, was earlier found not guilty of manslaughter, but guilty of assault, the registrar said.
He had been granted bail until his sentencing.
Constables Tevita Vakalahi and Manu Tu'ivai, were found not guilty of the charge, she said.
Last week a jury found Semisi Kalisitane Manu who shared a jail cell with Mr Fungavaka, not guilty of manslaughter but guilty of grievous bodily harm, she said.
He was also granted bail and would be sentenced next month.