Police have found two transactions totalling 60,000 baht that were made to a bank account held by Ekkalak Phaenoi, the 41-year-old Thai ex-Marine suspected of killing Lim Kimya, 73, a former Cambodian opposition MP, in Bangkok on Tuesday, a source said.
At 1pm on Tuesday, the first transaction of 30,000 was made, which allowed Mr Ekkalak to later withdraw 22,000 baht and use it to pay a policeman with whom he had pawned his gun, said the source, citing information from the ongoing investigation.
The officer in question, who has already been interrogated by investigators, insisted he had nothing to do with the assassination even though he had allowed the suspected killer to pawn his gun earlier, said the source.
About five minutes after the assassination, the other 30,000 baht was transferred to Mr Ekkalak's account, the source added.
Mr Ekkalak has been arrested in Cambodia's Battambang and now awaits extradition to Thailand.
His younger sister contacted local police in Chon Buri, where she lives, upon learning her brother was wanted in connection with Monday's assassination, said another source.
The sister told investigators Mr Ekkalak left a bag with her when they met up at a shopping mall in Chon Buri's Bo Win district the day he fled the country, that person added.
She said she was not aware there was a gun inside the bag until the police opened it on Thursday. She was released without any charge after questioning, said the source.
Inside the bag were a Smith and Wesson pistol, six bullets and two spent shell casings, which were all handed over to Chana Songkhram police, who are handling the probe, said the source.
So far, only Mr Ekkalak and Pich Kimsrin, a 24-year-old Cambodian man who is believed to have acted as a spotter in the assassination, have been named as suspects with arrest warrants issued, the police said.
Chana Songkhram police yesterday took the French wife of Lim Kimya and his elder brother to meet prosecutors at the Criminal Court on Ratchadaphisek Road for what was described by the police as an interrogation which needed to be conducted in advance as the two had to leave Thailand.
On Thursday, the French Foreign Affairs Ministry published a statement on its website condemning the murder of Lim Kimya.