The key piece of evidence that will most likely reveal whether the extrajudicial killing of Lahu activist Chaiyapoom Pasae at a military checkpoint in Chiang Mai was justified should be CCTV footage of the incident.
According to news reports, there are seven surveillance cameras in the area. Third Region Army commander Vijak Siribunsop also said he had seen the footage, which led to his incendiary comment: "If it were me, I might have put [the M16] on automatic firing."
Chaiyapoom, 21, a Mathayom 4 student known for his campaigning for ethnic rights and environmental protection, was shot dead on March 17.
It has been more than a week since the controversial shooting occurred but the army has not unveiled the crucial footage that could shed light on the extrajudicial killing.
Why?
Many people in society are asking the same question. If the army has nothing to hide, why can't it bring out the footage?
The National Human Rights Commission (NHRC) called on the army to reveal what was recorded by the surveillance cameras.
At the same time, more than 2,800 people have signed a petition on Change.org urging the army to share footage of the incident with the public.
"If members of the public are barred from seeing what is in the CCTV footage, would this be a case of state officials using their authority to censor the evidence and instill a sense of fear to the people? To be fair to both the officials and people, the CCTV recordings must be made available for the public to verify," said the petition.
It does seem like a reasonable request, and one that should dispel the scepticism surrounding the case.
The army's response was enigmatic. During a press conference on the teen's killing over the weekend, Col Jiradej Kamolpetch, commander of the 2nd Cavalry Regiment's Pha Muang task force in Chiang Rai in charge of narcotics control, said the army was in the process of "checking" the footage.
Why must the footage be "checked" before it is released, is anybody's guess. If the footage shows Chaiyapoom resisting an attempt by officers at the checkpoint to examine his car, in which officers said 2,800 meth pills were hidden, along with his trying to hurl a grenade at them in a bid to escape as claimed by the army, why withhold the proof?
The longer the army keeps delaying the unveiling of the CCTV footage, the more suspicious their motives will become in the eyes of the public.
It's even more puzzling that while the army sits tight on the security camera recording, it has been willing to disclose other circumstantial details.
During the weekend press conference, for example, Col Jiradej went to great lengths to reveal that the 22-year-old private who shot dead the student came from a poor family in the northeastern province of Buri Ram and had enlisted in the army because he wanted to relieve their hardship.
The task force commander even said that the private had been well-behaved.
It's difficult to see how the private's family background and his past behaviour have anything to do with the current question of whether the extrajudicial killing of the student activist was justified. As the army tries to avoid answering this crucial question, the atmosphere of distrust thickens.
Attempts by police to indicate that Chaiyapoom was a drug dealer might be part of the probe into an accusation that he had narcotics in his possession and tried to obstruct officials doing the searching but it is not exactly relevant to the question of the extrajudicial killing either.
While Chaiyapoom's family members told the NHRC that the activist had some income from selling coffee beans online, police on Sunday insisted that there were more than 30 unusual transactions in Chaiyapoom's account with money being transferred from three drug dealers in prison, according to a news report in Thai Rath.
Police Region 5 deputy chief Pol Maj Gen Phanudet Boonruang said it's clear from the transactions and that some amounts of money were withdrawn immediately after they had been deposited that the dead activist was not engaged in a normal business, according to the report.
It's one thing for authorities to prove that Chaiyapoom was involved in drug trafficking as claimed; it's another altogether to determine whether he deserved to be shot dead like that. And the first count, even if it's proven to be true, does not legitimise the second one.