Dismembered human body parts, apparently of an adult, that were found in a Tokyo pond in Meguro Ward's Himonya Park, were only partially decomposed, according to investigative sources.

Himonya Police Station investigators will carry out an autopsy Friday on the head, hip, legs and arms to try to determine when the person died and when the body parts were dumped in the pond. The police on Friday found the remaining portion of the torso but the parts of an arm have yet to be found. Divers are searching underwater for the remaining body parts.

The investigators are also collecting security camera footage in surrounding areas to see if anyone was acting in a suspicious manner.

An 80-year-old cleaner first discovered a right leg at around 10:35 a.m. on Thursday.

The six body parts were found floating separately in the pond, which is about 80 meters wide and 140 meters long. The body parts had not yet decomposed to just bones. The sources believe the parts were thrown into the pond at the same time recently but later floated apart.

The age and sex of the victim are not known.

The small, leafy park is located amid residential housing near Gakugei Daigaku Station on the Tokyu Toyoko Line. Rowboat rentals on the pond are popular with families.

The police are initially treating the case as one of the criminal discarding of a corpse, but it may soon be regarded as a homicide.