A family calling for what a rights group says is a long overdue investigation into the disappearance of their son during a violent demonstration in Phnom Penh some 19 months ago has been encouraged – if somewhat indirectly – to file a formal complaint with law enforcement if they hope for resolution.

In a statement posted to the National Police’s web page on Monday, deputy director Kirt Chantharith encouraged “families” to come forward, saying the force had never ignored victims’ pleas or been careless in fulfilling their obligations.

That announcement came just days after a prominent Cambodian human rights group, in honour of the International Day of the Victims of Enforced Disappearance, issued a statement urging the government to launch a “proper investigation” into the disappearance of 16-year-old Khem Sophath.

The teen was last seen bloodied and being placed into a tuk-tuk in the midst of a January 3 protest on Veng Sreng Boulevard, which saw police open fire with live ammunition as protesters hurled rocks and Molotov cocktails.

“Till now, the authorities have said that in Svay Rieng province or Phnom Penh, no complaints have been lodged by the family yet,” Chantharith said.

“Authorities, therefore, call for the cooperation from families to file complaints so that authorities can obtain some [clues] for the investigation to find the victims.”

But Khem Seun, Sophath’s father, says he filed a complaint with the Ministry of Interior after his son had been missing for a month, with no follow-up measures taken until two days ago when his village chief asked him about it.

“It has been nearly two years, and the village chief just came and asked when my son disappeared,” he said. “I wonder why he just came at this time.”

He added that he has no hope they’ll find his son now, since the boy’s friends said he was last seen with a gunshot wound inflicted by authorities.

“Where is the old complaint? I have no hope for justice,” he said.

Am Sam Ath, senior observer at rights group Licadho, stated that the announcement was made to give the illusion of the rule of law since civil society organisations have recently insisted on a renewed investigation.

“In fact, the family did file a complaint and the family and witnesses also gave testimonies at the Ministry of Interior,” he said. “The statement was given to show that for this case, the government is carrying out an investigation just to follow procedure.”

At least five people died during the protests on Veng Sreng, while 23 were arrested and scores more civilians and security forces injured.

According to Interior Ministry numbers, the total cost of damages during the post-election period, from July 28, 2013, to early January 2014, totalled an estimated $100 million.