When a crime is committed in an isolated rural spot it is often difficult to catch the criminal, without eyewitnesses or closed-circuit cameras to provide leads.
But Saraburi police recently followed a limited trail of clues to nab a 19-year-old suspect who allegedly raped a woman and stabbed her to death earlier this month.
On the night of Dec 11, Rungrat Phusurin, a 48-year-old shop assistant, drove her motorcycle alone along Kutnokplao Road in Muang district.
A native of Saraburi's Kaeng Khoi district, Rungrat had finished her shift at a shopping mall in town and was on her way home. She never made it. Her body, carrying stab wounds, was found by a villager just before dawn the next morning. No one saw what happened to her.
Chief investigator Pol Col Aphichat Wannaphak said police were in a bind. They found few clues at the crime scene, and villagers in the area were afraid for their safety, especially the women, given the brutal nature of the crime.
Initial examinations found that Rungrat suffered severe injuries, was raped and stabbed to death, and her valuables stolen.
Pol Col Aphichat, a superintendent for Provincial Police Region 5, was called in to lead the investigation. There were no security cameras in the desolate area.
However, the officers tried to picture what happened that night by inspecting the victim's motorcycle left lying on the road. A closer look at the bike and nearby spots led them to conclude the attacker took action to force her off the road.
An examination of Rungrat's belongings scattered at the scene also helped investigators to determine the direction in which the murderer might have fled. But these clues were insufficient to lead the officers to any suspect.
Pol Col Aphichat decided to change tack. Investigators began interviewing people in the area to try to uncover recent suspicious activity or anything out of the ordinary.
After days of searching, they found a man who said he saw a teenager riding a motorcycle without a helmet near the scene on Dec 11.
The rider's behaviour caught his eye because he kept following passing motorcycles driven by lone women.
What Pol Col Aphichat's team obtained from this witness helped police narrow down the possible whereabouts of the suspect.
His not wearing a helmet suggested he did not live far from the crime scene because he would have faced police checkpoints if he had travelled any distance, the investigators said.
The officers also obtained a sketch of the suspect following their talk with the witness. Another witness later recognised the man in the sketch and identified him as a teenager called Mag, his nickname.
He had recently moved to Saraburi and rented a hut in tambon Huai Haeng in Kaeng Khoi district.
Investigators went to the suspect's home on Tuesday, intending to only observe his behaviour. But the young man spotted the officers and immediately fled to a nearby hill.
The officers recruited villagers to surround the hill, and three hours later they arrested him without a fight.
The suspect, identified as Somkhit Choiwichian, allegedly confessed he raped and killed Rungrat. Police also seized from him a 56cm knife and a mobile phone that belonged to the victim.
According to Mr Somkhit's accounts, he attempted to rob villagers riding on Kutnokplao Road because the area is quiet and has no lights.
When he saw the victim, he sped alongside her and kicked her motorcycle.
Rungrat badly injured her neck in the crash. He made off with her mobile phone, her ATM card and password, and spare cash.
He rode to a nearby ATM but found she had only 30 baht in her account.
Angered by this, Mr Somkhit came back to the crime scene and raped the woman, who was still unable to move.
When she tried to resist, he stabbed her to death in a fit of anger, according to his confession statement.
"This was a crime that was quite cruel, though it was committed by someone so young," Pol Col Aphichat said.
Worse, this was not his first crime. Police say that three years ago, Mr Somkhit and an accomplice were involved in the murder of a man who they attempted to rob in Saraburi's Nong Don district.
He was arrested and convicted of the murder. The court sentenced him to 17 years in jail, but since he was a minor at the time he was sent to a remand home in the province instead of prison.
In June this year, after two years in jail, he escaped. Police suspect he was keen to avoid being transferred to an adult prison, which is required by law when he turns 20.
He was on the run, with little education and no work skills. As such, it wasn't long before Mr Somkhit ran into trouble with the law again.
This time, however, he will be tried as an adult for a second capital offence.
Contact Crime Track: crimetrack@bangkokpost.co.th