The Thai man who admitted to killing Yoshinori Shimato, a 79-year-old Japanese teacher who had been missing since late September, has confessed to killing another Japanese man, a Thai police official said Friday.

The confession was made by Somchai Kaewbangyang, 47, who is thought to be a former husband of Phornchanok Chaiyapa, also 47. The couple were arrested Thursday for allegedly killing Shimato and abandoning his body.

According to Thai police and other sources, the other Japanese is Katsutoshi Tanaka, who died after falling down stairs in a Bangkok suburb about 10 years ago. Police at that time ruled out foul play.

Phornchanok reportedly received a huge sum of insurance money after Tanaka's death.

A woman claiming to be the daughter of Tanaka and another Thai woman has asked the police to reinvestigate her father's death after learning Shimato was allegedly killed.

The police found severed body parts from Shimato's corpse in a canal near Bangkok after conducting a search based on the Thai man's statement.