The sister of a Thai political activist who vanished in Phnom Penh a year ago on Friday demanded answers from the authorities, after 12 months without any progress in the case.
Wanchalearm Satsaksit, who was wanted by Thai police for running an acerbic anti-government Facebook page, was dragged into a car in broad daylight in the Cambodian capital.
There has been no trace of him since, and on Friday his sister Sitanun handed documents to the justice ministry in Bangkok demanding a proper investigation.
"I'm here today to ask what the Ministry of Justice has done after a year," Sitanun told reporters.
"Thai and Cambodian authorities should have an answer by now after a year has passed. We want sincerity from both authorities on this case."
Rights group Amnesty International called on Thailand to launch an independent probe into the disappearance, saying the Cambodian authorities had failed in their duty.
"This negligent investigation is at a standstill. The past year has been marked by foot-dragging, finger-pointing and the absence of any credible effort to examine what really happened to Wanchalearm," Amnesty International's Ming Yu Hah said in a statement.
Wanchalearm was living in Cambodia after fleeing Thailand in the wake of the 2014 coup that brought Prayut Chan-O-Cha -- then army chief and now prime minister -- to power.
The 37-year-old was wanted for sedition and breaching Thailand's Computer Crimes Act -- broad legislation that rights groups say is abused to silence critics.
Cambodian police say they have made no headway in the case, but Thanakrit Chitarirat, secretary to the Thai justice minister, insisted there would be "progress this month".
But Thai investigators say that because the disappearance happened in Cambodia, the onus is on police there to lead the enquiry.