The upper part of a man's body found floating in Khlong Saen Saep in Bang Kapi district on Saturday has been identified.
Police have also located a thigh, believed to belong to the same man, about four kilometres away.
The body, from head to waist, was found in the canal at the end of Soi Ramkhamhaeng 85/3 on Saturday evening.
The head of the bearded man, aged 49, had a knife wound, about six inches long.
A source at the Central Police Forensic Science Division said the body was identified as that of Winai Jaisaen, a motorcycle taxi driver, using fingerprints from both thumbs.
Investigators are in the process of searching for his relatives to determine the cause of the murder and hunt down the culprits.
Deputy police spokesman Kritsana Pattanacharoen on Sunday confirmed the body had been identified, although he did not reveal the man's name.
He noted progress has been made in the probe.
Police chief Chakthip Chaijinda instructed investigators to handle the case carefully and the investigation must rely on forensic evidence.
The police chief has ordered investigators to expedite their efforts to resolve the case and apprehend the perpetrators as soon as possible so as to boost public confidence.
Police in Wang Thonglang were alerted to the discovery of a thigh in Khlong Saen Saep close to Bueng Rama IX at 10am on Sunday.
Pol Col Suriya Nakkaew, deputy chief of Metropolitan Police Division 4, said the thigh was cut in a similar way to the upper body and that it was likely that it belonged to the retrieved corpse found in Khlong Saen Saep.