The body of a 17-year-old school boy with Chinese nationality was found last week in a central Japan lake, with foul play strongly suspected due to the circumstances surrounding his death, police said Tuesday.

Prefectural police have set up a special team to investigate the suspected murder of Ukawa Saito, who was attending a correspondence high school in Fukuroi, Shizuoka Prefecture, after his body was found in Lake Hamana on Friday.

According to the investigative team, police received an emergency call around 3:45 p.m. Friday from an angler saying they had dragged up a body while fishing at the lake.

The body was identified as Saito, who had been reported missing by his family two days earlier. An autopsy conducted Tuesday showed that he had drowned and had been dead for about a week, with his body bearing multiple bruises, according to the police.

Saito was confirmed to have been at an acquaintance's house in the city of Hamamatsu in the early hours of Feb. 5, the police said. Investigators are questioning family members and others who knew him to determine if Saito had been caught up in any trouble.

A 74-year-old man working near where the body was found said the area is usually quiet, with only occasional visitors such as anglers and local residents for exercise.

"It is not the kind of place high school students come, especially at night when there are no streetlights," he said.