The Royal Thai Police have compromised their integrity by going back on their word after the use of teargas during the rally at Pathumwan intersection in mid-October.
It's not clear why the officers denied employing the agent earlier.
And it's also not clear what protocol the police referred to when they claimed they were following international crowd dispersal standards in using water cannon and chemical irritants.
What is clear, however, is the police are exposing themselves to scepticism, not only about their crowd-handling abilities but also their honesty as frontline officers.
During a parliamentary hearing on Monday, deputy chief of the 2nd Crowd Control Division Chawalit Runsiri admitted that teargas was mixed in with water sprayed at anti-government demonstrators.
At that time, many demonstrators and journalists complained that their faces, eyes and skin were irritated by the spray, which the police claimed was tinted blue due to the addition of a harmless blue dye so the protesters could be tracked down and identified.
This lack of transparency shows a level of irresponsibility unbefitting of law enforcement officers even though they branded the protests as unlawful.
Police spokesman Kissana Phattanacharoen insisted that no teargas had been used immediately after the incident.
The Pathumwan dispersal has prompted many people to question whether the police used disproportionate force to handle an otherwise peaceful demonstration.
At the time, officials reportedly brushed aside the claim that teargas was used as "fake news".
How do law enforcement officers expect the public to react after finding out hey had been lied to and that teargas was indeed employed that day to disperse the crowd?
Lt Col Chawalit insisted that riot police followed universal standards on crowd control and resorted to teargas only after the water cannon failed to force them to retreat.
He also told the parliamentary hearing that only a small amount of teargas was mixed in with the water so he believed it would not be harmful to the protesters.
But why did the police keep the truth from the demonstrators and general public?
Such dishonesty will likely only escalate tension between police officers and demonstrators when they face off in future rallies.
The coverup will also cast doubt about the police's work in general and further erode public trust in the police commission, which many people already wished to see reformed.
Police denials about teargas has brought into question its claim that the crowd control techniques are up to standards.
According to the United Nations Office of the High Commission on Human Rights, water cannons should only be used "in situations of serious public disorder where there is a significant likelihood of loss of life, serious injury or the widespread destruction of property".
The Pathumwan rally did not seem to match this critera. Neither did the recent gathering in front of the Grand Palace where a water cannon was also used.
Now that the police have come clean over the use of teargas, they should clearly lay out their current crowd control protocol as well as any measures they intend to implement in the future for the sake of transparency and public safety.