BANGKOK -- A suspected hitman accused of killing a Cambodian former opposition lawmaker in a brazen attack in Bangkok was handed over to Thai authorities on Saturday from Cambodia, where he had been arrested after crossing the border.

Thai national Ekkalak Paenoi, 41, faces charges including premeditated murder in the Tuesday shooting death of Lim Kimya, 74, in the Thai capital.

"The suspect confessed to the crime and to being the person in the arrest warrant," Somprasong Yentuam, assistant national police chief, told reporters. "He looked stressed."

Ekkalak, a motorcycle taxi driver who police officers told Reuters was a former marine, was taken to Bangkok after Thai police coordinated with Cambodian authorities. A Thai court issued the warrant and he was arrested on Wednesday.

Lim Kimya, a Cambodian and French citizen, was killed by a gunman firing three shots, hours after arriving from Cambodia with his wife and brother and travelling to Bangkok by bus, police have said.

He was a member of the Cambodia National Rescue Party, a popular opposition group that was dissolved by a court over an alleged treason plot ahead of a 2018 election. The party dismissed the alleged plot as a fabrication.

Cambodia's government, led by the Cambodian People's Party for more than four decades, has conducted a ruthless, years-long crackdown on its opponents, with scores of politicians and activists receiving prison terms, many in absentia, and hundreds more fleeing into exile. It has denied persecuting the opposition.

Lim Kimya was not a prominent member of the opposition movement. Police and the Thai government said they had not to determined the motive for his killing.