The probe into the killing spree involving five homeless people in Pathum Thani and Bangkok has been wrapped up with DNA test results and other evidence now pointing to the most likely murder suspect, police say.
Investigators are confident the investigation is airtight, thanks to the DNA tests they ran to back the charges against the suspected serial killer, a Myanmar national identified as Jimmy.
Mr Jimmy was arrested on Oct 7 near the Mor Chit Bus Terminal after police spotted the 20-year-old suspect wearing a blood-stained shirt. But while investigators believed this was their big break, Mr Jimmy bluntly insisted the blood was his own and was the result of a self-inflicted wound.
Police now believe this was the final killing of a homeless woman during a murderous spree by serial killer "Jimmy") (Photo by Tanaphon Ongarttrakul)
The forensic evidence and the similar nature in which the victims were murdered led police to conclude Mr Jimmy must have killed the three men and two women whose bodies have turned up since early this month.
On Oct 4, the bodies of a man, Suporn Kokkran, 25, and a woman, Supaporn Kongyudee, 38, were found near the Princess Mother National Institute for Drug Abuse Treatment, also known as Thanyarak Hospital, in Pathum Thani's Thanyaburi district.
Supaporn's body was dumped in a canal in front of the hospital, not far from the spot where Suporn's body was found, police said.
Two days later, the body of a third victim, Sathien Sornchai, 40, was discovered near the same hospital. His throat was slashed and there were stab wounds to his abdomen and buttocks. Sathien also had his hands tied with an electrical wire.
The victims sold scraps of rubbish to make a living. The suspect, Mr Jimmy, is also believed to be a homeless scavenger.
Investigators believe the victims fell prey to the same killer because they were murdered in a similar manner. On top of that, DNA test results showed some of the blood stains on Mr Jimmy's shirt carried Suporn and Sathien's DNA, Pol Lt Gen Sanit said.
Officers suspect the motivation behind the murders may have been robbery or sex. However, no evidence has been found to indicate any money or valuables were taken.
Police also believe Supaporn had been raped prior to her murder, according to deputy police chief Chalermkiat Sriworakan.
A witness told police she was approached by Mr Jimmy at a restaurant in the Rangsit area in the early hours of Oct 6. The suspect allegedly said he wanted to have sex with her and tried to force himself on her but she managed to escape.
Another witness told police he saw Mr Jimmy near the spot where Supaporn was killed around the time of the murder.
A six-year-old boy claimed to have seen Mr Jimmy hit Suporn before slashing his throat and tying his wrists, investigators said.
The Pathum Thani killings prompted a manhunt for the suspect with the aid of footage obtained from a security camera. A traffic policeman later spotted Mr Jimmy sleeping near the bus terminal and he was taken into custody on Oct 7 under an arrest warrant.
Mr Jimmy's physical appearance matched the image of the suspect in the footage, according to police.
According to the investigation, Mr Jimmy had earlier ridden his bicycle from Pathum Thani to Bangkok.
Not far from where he was caught, the body of a fourth victim was found on Oct 9.
Rampha Panchaphonlawet, a 58-year-old from Chiang Rai, was found dead under a ramp at the Lat Phrao intersection. Rampha was homeless, like the other three victims, and living under the ramp.
Her body bore multiple stab wounds and her hands were tied with a nylon strip.
Police later found a blood stain on the shirt worn by Mr Jimmy that matched a blood sample taken from Rampha, according to Pol Lt Gen Sanit.
Lab test results suggested Mr Jimmy also had a hand in the murder of newspaper seller Wanchai Noymontri, or Lung Yim, 56, found dead at a mini-park on Rama VI under a section of an expressway in Bangkok on Sept 5, police said. DNA traces collected from a piece of wood used to club Wanchai matched that of Mr Jimmy.
Mr Jimmy, who is being held in Bangkok, has been charged with the first three murders and inquiries are continuing into the others.
Contact Crime Track: crimetrack@bangkokpost.co.th.