Thai police said Tuesday they have detained a Thai woman and her husband in the disappearance of a 79-year-old Japanese man in Bangkok.

The police quoted the husband, also a Thai, as saying the Japanese, Yoshinori Shimato, died of a heart attack after going to a hospital Sept. 21, and he cut the body into pieces and dumped them in a canal.

The man said he acted alone and denied that he killed Shimato, according to the police.

The police searched a canal in Samut Prakan, adjacent to the Thai capital, Tuesday night and found several plastic bags that have yet to be checked.

The police said Shimato, a Japanese language teacher, has been unaccounted for since he went to a Bangkok hospital with the woman on Sept. 21.

The woman was arrested a few days ago on a theft charge for withdrawing 700,000 baht ($21,700) using an ATM card belonging to Shimato. She was released but detained later along with her husband for questioning. The police found them in Ang Thong province in central Thailand.