Police have arrested Rachadech "Nam Oun" Wongtabutr on three charges relating to the death of product presenter Thitima "Lunlabelle" Noraphanpiphat.
The 25-year-old was apprehended at a petrol station in Thon Buri district about 1am yesterday when he stopped to refuel his car, in which his parents were also travelling.
According to security footage, Mr Rachadech was the last person seen with Thitima before her body was found in the early hours of Sept 17, on a sofa in the lobby of a condominium building where Mr Rachadech lives.
Mr Rachadech had earlier refused to open the door when police went to his condo on Ratchadaphisek-Tha Phra Road to show him a warrant for his arrest.
He was later taken to Metropolitan Police Division 8 and then to Bukkhalo police station for an interrogation which lasted 11 hours.
He was charged with unlawfully detaining Thitima in a way that caused her death, sexual assault, and committing an act of indecency.
Metropolitan police chief Pol Lt Gen Suthipong Wongpin said at Bukkhalo police station that Mr Rachadech admitted to being the man seen in the surveillance footage carrying the unconscious Thitima into the condominium building on the evening of Sept 16, and leaving her on a sofa in the lobby the next morning. Her body was later found by a security guard.
However, he denied all charges and insisted he did not know that Thitima was dead, saying he believed she was "just drunk", Pol Lt Gen Suthipong said.
The Bangkok police chief said investigators will look into whether any other person at the party in Nonthaburi's Bang Bua Thong district -- where Thitima was hired to serve drinks before the incident at the condo, and where the accused was also present -- should also be charged.
According to police, an autopsy found Thitima died of alcohol poisoning, with a blood alcohol concentration of 418 milligrammes per 100 millilitres -- a level that can lead to unconsciousness and even death.
Police said that after Mr Rachadech was interrogated and charged, he was taken to where the party was held to point out where Thitima had sat and drank.