A Thai court on Wednesday issued an arrest warrant for an adviser to Cambodian strongman Hun Sen, accusing him of recruiting others to commit “premeditated murder” in the brazen killing of a former Cambodian opposition politician in Bangkok last week.

The warrant was the strongest indication yet that Lim Kimya, who was killed on a busy street, was the victim of a political assassination. He was a former member of the National Rescue Party of Cambodia, an opposition party that was dissolved under pressure from Mr. Hun Sen, who ruled Cambodia as prime minister for nearly four decades. Mr. Hun Sen handed that job to his son Hun Manet in 2023, but remains the leader of his political party and the country’s senate.

The person named in the arrest warrant is Somwang Bamrungkit, 42, a dual Thai-Cambodian national known in Cambodia as Ly Rotanakraksmey. Thai prosecutors filed three charges against him, including one for carrying a firearm and firing a firearm. His current whereabouts remain unclear. .

Sok Eysan, a spokesman for the Hun Dynasty Cambodian People’s Party, said that although Mr. Ly Rotanakraksmey was the adviser of Mr. Hun Sena, “what he does illegally is the responsibility of that person.” Mr. Hun Sen has appointed dozens of advisors, and the exact nature of his relationship with Mr. Ly Rotanakraksmeyem was not immediately clear.

Last Tuesday, Mr Lim Kimya, 73, who was a dual French and Cambodian citizen, was shot dead by a gunman after he got off a bus from Cambodia to neighboring Thailand. The attacker fled on a motorcycle and boarded a pickup truck before crossing into Cambodia. But in the following days he was arrested and extradited to Thailand, where authorities identified him as Ekaluck Paenoi. He confessed to the killing but told Thai investigators that he could not reveal the mastermind for fear of his family’s safety.

Cambodian dissidents, including Sam Rainsy, who once led the CNRP, said the ultimate blame for the killing lay with Mr. Hun Sen.

The killing was seen as a major escalation in a campaign of transnational repression by Cambodia, which in recent months has secured the deportation of dissidents from Thailand and Malaysia. This was condemned by France, which said it would closely monitor the investigation by the Thai authorities.

“It sends a frightening message that no one is safe,” said Elaine Pearson, Asia director at Human Rights Watch. “If they can target someone of that size and do it in such a blasé way, on the streets of central Bangkok in daylight, in front of CCTV footage, imagine what they could do to someone who doesn’t have a high profile, who isn’t an opposition politician and who doesn’t have another nationality. “

Ms Pearson said that after the murder, Cambodians in Thailand contacted her organisation, fearing for their safety. She said there is an urgent need for foreign governments to quickly resettle Cambodian refugees and exiles.

Before it was crushed, the Cambodia National Rescue Party was the biggest threat to Mr. Hun Sen’s rule. Mr. Ly Rotanakraksmey, a fugitive, was a CNRP official in Thailand. But in 2022 he joined the CPP and became advisor Mr. She Sen last January.

Separately, Thai media reported that Interpol had sought the arrest of Pich Kimsrin, a 24-year-old Cambodian identified by Thai authorities as a so-called bystander in the murder. Mr. Pich Kimsrin appears to be the younger brother of Pich Sros, the pro-government politician best known for filing the lawsuit that led to the dissolution of the CNRP in 2017, according to a family photo and his birth certificate. Mr. Pich Kimsrin is still at large.

Mr. Pich Sros is a member of the government’s Supreme Advisory Council, which gives him a rank equivalent to senior minister and government adviser, and is the founder of his own minor political party, the Cambodian Youth Party, which is aligned with the CPP. He declined to comment.

In May 2023, Mr. Pich Kimsrin was appointed deputy manager of Phsar Kandal market in Phnom Penh, subordinate to Kieng Chak, second adviser to Mr. Hun Sen.

Muktita Suhartono contributed reporting from Bangkok.