A security guard at Thitiwong apartment in Soi Bang Khunnon 12 rushed to call police after he spotted a man's leg while helping Phonsuri Diphaeo, 36, take her belongings out of the room late Sunday morning.
The man, identified as Prasit Sombunyanon, 47, is Ms Phonsuri's husband and the room's owner. He had suffered from muscle weakness (myasthenia gravis) and allegedly had often scolded and assaulted by his wife, said motorcycle taxi driver Sarawut Ngamthae.
Police detected traces of drugs in her urine, but so far have found no other major clues to the killing as Ms Phonsuri had given conflicting information to investigators.
An initial inspection found Mr Prasit had been slashed about the body and his hands and ankles were also severed.
After searching for other parts of the victim's body in a canal near the apartment after witnesses said Ms Phonsuri earlier threw a bag into the water, police recovered the man's head, said Pol Maj Parinya Chansuriya from Bang Khunnon Police station.