Duangchan Chaiphengchan can hardly sleep after her 18-year-old son was killed, as the family remains in the dark about the circumstances surrounding his death.
The family has little idea of what happened to Hatsadin on the night of March 4 in Chachoengsao. As each day passes, their trust in local police is dwindling due to the fact the investigation has made almost no progress in over two months.
"We badly need the CSD's help," Ms Duangchan said as she, together with her husband, on Thursday lodged a complaint at the Crime Suppression Division (CSD) in Bangkok.
"There have been news reports about the police nearly catching the suspects but nothing happens."
The last time the family spoke with Hatsadin was when he was out drinking with his close friend in Phanom Sarakham district.
Soon after, Hatsadin, a third-year student at Phanom Sarakham Industrial and Community Education College, went missing. His body was found 12 days later in a eucalyptus plantation near Khao Hin Dang monastery in Sanam Chai Khet district in the province.
According to Ms Duangchan, Hatsadin had told the family on March 4 that he would meet his friend before coming home on his motorcycle. The teenager talked to his father on the phone around 10pm saying he was going to return home.
Initially, the family thought Hatsadin might have been drunk and decided to stay overnight at his friend's house but they never saw him again until they heard the news from the police.
The Bangkok Post attempted to contact the Khao Hinson police on Thursday but no one picked up the phone.
Hatsadin's friend, whose name has not been disclosed, said he saw Hatsadin off near his house after drinking.
Current evidence and accounts have prompted CSD investigators to look for more clues which might shed light on Hatsadin's disappearance.
They said it is was too soon to comment on whether he had been murdered.
A source close to the investigation said that even forensic experts could not identify the cause of death based on the autopsy results.
The examination of his body showed no wounds caused or broken bones.
When the police found the body, parts of his internal organs were already decomposed as Hatsadin had been dead for nearly two weeks.
"But we will help the family figure out this case," Pol Col Arun Wachirasisukanya, chief of the CSD's subdivision 2, said.
The investigators have vowed to gather more evidence in the case.