Former Cambodia National Rescue Party member Ismail Pin Osman was arrested in Phnom Penh on Wednesday for alleged human trafficking, though police officials offered little detail on why he was taken into custody.

Pin Osman, who is listed as a licence plate seller on his arrest warrant, was arrested by anti-human trafficking police, but department head Pol Pithey declined to clarify the circumstances surrounding the arrest beyond noting that it “followed a complaint”.

Ysa Osman, a former CNRP activist in the ethnic Cham community, confirmed that Pin Osman had been arrested in Phnom Penh’s Russey Keo district and was being held at the National Police headquarters.

A police summons from November requests Pin Osman appear at the Interior Ministry’s Anti-Human Trafficking and Juvenile Protection Department for allegedly sending female workers overseas. His February 5 arrest warrant cites a complaint from a person named Los Nass.

Former CNRP lawmaker Mao Monyvann said he had only heard of the arrest and that Pin Osman had stood as a reserve candidate in Kampong Cham in the 2013 national elections.

“After the election, he was a member of the CNRP working team in Tbong Khmum [province],” he said, adding that the case could be linked to the ruling party’s efforts to get opposition officials to defect.

Following the CNRP’s forced dissolution in November, the ruling Cambodian People’s Party made a major push to encourage CNRP members to switch parties, with many CNRP activists and elected officials reporting harassment and surveillance as part of the effort.