It seemed police had done a good job when they arrested a father and his son for kidnapping and extortion, backing their accusation with security camera footage, the suspects' vehicle licence plate and a victim's account.
But it turned out later that the pair might have been made scapegoats when they countered the charge with new evidence that caused the Metropolitan Police Bureau to reinvestigate the incident which occurred four months ago in Bangkok.
City police chief Chantep Sesavej said he told officers to look into the discrepancies. However, the step came after the alleged irregularities dealt a blow to the police's image and tainted people's trust in the investigation process.
This is not the first time doubts have been raised over police work. Legal disputes over the "real" culprits in some criminal cases have long been a thorny issue between officers and the accused. What happened to lorry driver Mongkhon Khananut, 48, and his son, Ekkalak, a 28-year-old storehouse worker, is just the latest such case.
They too will be victims if the evidence they have mustered fails to prove their innocence.
According to an initial investigation, the two abducted a tomboy and extorted cash worth 150,000 baht from her while pretending to be policemen. The woman, whose name was not revealed, was detained from 12.30pm to 8pm on April 5.
After her release, she complained to police and told officers she remembered the abductors drove a white Toyota Vios with the licence plate "CHO NGO 6781".
It was this evidence that led Wang Thong Lang police to arrest Mr Ekkalak as his car had the same plate. The vehicle was being repaired at a garage owned by a second-hand car seller in Pathum Thani's Thanyaburi district.
A further investigation found he is a son of Mr Mongkhon whom the officers suspected colluded with Mr Ekkalak to plan the abduction.
Warrants for their arrest were issued on April 21 and officers from the Crime Suppression Division helped with the arrest.
CSD officers nabbed Mr Ekkalak on May 15 at his workplace in Ayutthaya.
His boss told him the officers arrived at the warehouse and "when I came out, they suddenly detained me," Mr Ekkalak told the Bangkok Post.
Mr Ekkalak was stunned when police claimed he had colluded with six other people, including his father, to kidnap a woman in Bangkok and force her to hand them the money.
"But I hadn't visited Bangkok in 13 years," Mr Ekkalak said. "I had also not been with my dad for a long time."
Mr Ekkalak also told the officers he had no reason to extort money because he makes enough from his current job to take care of his family.
The man was later handed over to Wang Thong Lang police who took him to Bangkok. They told him to phone Mr Mongkhon, asking his father to report to the officers at Wang Thong Lang station.
After being jailed for a night, the abducted woman met investigators to identify suspects. To his surprise, Mr Ekkalak said, the woman pointed the finger at him.
He was then told to watch a video clip obtained from a security camera installed at a petrol station where the crime took place.
The investigators insisted he and his father were in the clip though "the picture was not clear," Mr Ekkalak said.
However, the vehicle licence numbers could be read and they matched his car's.
This case has some oddities, especially the woman's account, which seemed "unusual", said Atchariya Ruangrattanapong, chairman of Help Crime Victim Club, who is helping Mr Ekkalak and his father.
The woman claimed she was with Mr Ekkalak and Mr Mongkhon though the defendants proved the accusation had no grounds by presenting security camera footage showing their whereabouts on April 5.
That day Mr Mongkhon was working in Nakhon Phanom while his son was having his fingerprints scanned before entering a storehouse in Ayutthaya, Mr Atchariya said.
The vehicle licence numbers can be also explained. Mr Atchariya suspects the one seen at the crime scene was forged by using authentic numbers belonging to Mr Ekkalak's car. All evidence in the case has been sent to officers for the re-investigation, he said.
Mr Mongkhon said he was stressed when he learned his son had been detained and he was also a suspect.
After turning himself in to police, Mr Mongkhon took two witnesses to meet police to confirm he had been in Nakhon Phanom between April 5 and 6.
"I also had security camera footage showing my friends and I cooked and had meals together," Mr Mongkhon said.
His son also raised another question about police work. He knew the officers were performing their duty, but he did not understand why they did not issue a summons. In his view, it seemed police intentionally skipped this step and made an abrupt arrest.
Mr Ekkalak said the abduction plot appeared senseless because the amount extorted was less than his wage and hardly worth the risk. "If I'm sentenced to jail for two or three years, how will my wife and my children live?" he said.
The suspects said they were lucky to be temporarily released during the investigation. However, that freedom, which allows them to fight their the case, has a cost.
They had to seek loans to pay 100,000-baht bail each and are now paying monthly installments -- 7,000 baht for Mr Ekkalak and 5,000 baht for his father.
The pair hope the accusation will be eventually dropped, following help from Mr Atchariya who advises them what they have to do before the case is forwarded to prosecutors.
Pol Lt Gen Chanthep insisted the officers will handle the case in a transparent manner, ensuring justice for all sides.
"But what if I was a farmer working in a field and could not find evidence to show I was not at the crime scene that day," Mr Ekkalak asked. "Do I still receive justice?"