Deputy national police chief Srivara Ransibrahmanakul has vowed to arrest a former Bangkaew singer, Pongpet "Ball" Sinsuwan, if he was involved in the fire that killed his girlfriend last month.
Investigators could ask the court to issue a warrant for his arrest if there is evidence to back an accusation, Pol Gen Srivara said.
He was speaking as the woman's family Thursday asked him to look into the case which they do not believe resulted from an accident.
Supanee "Benz" Sin-anantrakul, 27, died in a blaze which broke out in the two storey family home of the 34-year-old singer in the Thanya Thani housing village, Lam Luk Ka district of Pathum Thani, on Dec 16.
Her relatives want police to figure out why Supanee had wounds on her body which occurred before the blaze, said activist lawyer Atchariya Rueangratanapong, who accompanied the family to the Royal Thai Police headquarters on Thursday.
An autopsy carried out by the Central Institute of Forensic Science found Supanee suffered five wounds from the fire and "seven other wounds" before her death.
The seven wounds are mainly bruises that were not caused by Supanee herself, but the institute cannot conclude they resulted from physical assaults.
Supanee had stayed with Pongpet's family supposedly after a row with her father, Banyat, who earlier told reporters the former singer was a hothead who assaulted his daughter repeatedly for about six months while they were together.
The family also suspected someone, including police, might have tampered with evidence after the incident, Mr Atchariya said.
The crime scene was not appropriately sealed off, which raised doubts over possible irregularities during the inspection, he alleged.
Also, officers from the Technology Crime Suppression Division who examined Supanee's mobile phone were accused of deleting part of the dialogue in her Line chat application.
The conversation was believed to concern Supanne's complaint over attacks by Pongpet, Mr Atchariya said. Investigators are looking into the claims, Pol Gen Srivara said.
