From the beginning, police from the top down, from national chief Pol Gen Somyot Pumpanmuang to cops in Surat Thani province who have jurisdiction over Koh Tao, have been under heavy pressure to show results of the high-profile murders of two British tourists on the tourist island on Sept 15.
The appalling crime has attracted both Thai and foreign media attention, especially in the British media, not only because the victims, David Miller and Hannah Witheridge, are British but also for the fact that Koh Tao is a popular haven for backpackers from throughout the world.
A huge police force was sent to the island to carry out an investigation and hunt for the suspects.
Hundreds of Myanmar migrant workers working on the island and in fishing boats as well as some locals were rounded up for DNA tests as forensic investigators scoured the scene to look for evidence while others examined video footage from surveillance cameras at the scene and nearby in their desperate search for suspects.
For the first three weeks after the crime took place, police claimed their investigation was progressing yet no credible suspects were arrested although some Myanmar migrant workers and a few Thais were under suspicion.
Then in the fourth week, police claimed they had a breakthrough as the DNA samples of two Myanmar workers, Win Zaw Htun and Zaw Lin, matched the DNA found in the body of Ms Witheridge.
The police also claimed they had a key witness, a Myanmar worker, to testify against the duo.
In his weekly address on Friday night, Prime Minister Prayut Chan-o-cha admitted he was surprised too with the authorities' quick success in capturing the suspects.
He defended the police against widespread criticism the suspects might be scapegoats saying that he didn’t believe any police would dare to frame someone in this high-profile case.
But as far as the police are concerned, the heat against them appears to have increased despite the arrest of the two Myanmar suspects.
The suspicion of foul play is widespread among both Thais and foreigners.
In Tokyo last week, a group of Myanmar workers demonstrated in front of the Thai embassy calling for fair treatment of the suspects.
Myanmar President Thien Sein was quoted to have told Prime Minister Prayut during his visit to Myanmar last week the investigation into the Koh Tao murder case needs to be clean and fair.
“The pressure to be seen to be solving an appalling case that has garnered considerable attention should not result in a violation of rights,” Amnesty International’s Asia Pacific programme director Richard Bennett said in response to allegations by the suspects that they were made to confess under duress.
Win Zaw Htun and Zaw Lin reportedly told their lawyer hired by the Myanmar embassy in Bangkok that they were tortured by the police to make them confess to the crime.
Had the Thai police’s reputation been intact and trustworthy, they should have won the praise of the public for their performance in resolving the murder case instead of having to fend off the suspicion the suspects might be scapegoats.
Khunying Porntip Rojanasunant, director of the Justice Ministry’s Forensic Medicine Institute, said the police mishandled the case from the start when they sent investigators and ordinary doctors to the crime scene instead of forensic experts.
This might have resulted to some crucial evidence being overlooked or vanishing, she said.
Police treatment of some high-profile cases in the past leaves much to be desired.
Take for example the abduction and murder of businessman Akeyuth Anchanbutr, a vocal critic of former prime minister Thaksin Shinawatra and the Pheu Thai government.
Despite public suspicion the murder might be politically motivated, the police in charge of the case concluded it was a straightforward robbery case and the culprit was the victim’s driver, Santiparb Pengduang, aka Ball, and the motive for the crime was money.
In August however, Akeyuth’s lawyer, Suwat Apaipak, claimed Santiparb told his lawyer from prison that the real murderers were men in uniform and that he didn’t kill the businessman.
Santiparb also claimed that he was cheated of the pay he was supposed to receive from his involvement in Ekkayuth’s abduction.
Mr Suwat later said he decided to quit the case because he was afraid of his own life.
He added the victim’s family also didn’t want to pursue the case.
Then there are the enforced disappearance cases of Muslim human rights lawyer Somchai Nilapaichit and Saudi businessman Muhammed al-Ruwali. Men in uniform were believed to be involved for their disappearance.
How the Koh Tao murder case will transpire depends on the prosecutors who will decide whether to indict the suspects or not, and eventually the court, which will have the final say.
But with all eyes watching especially from Myanmar and Britain, police must be sure they have a watertight case and the suspects are real, otherwise some heads must roll.
Veera Prateepchaikul is former editor, Bangkok Post.