One of 13 cases received has been dismissed, while the office is investigating 11 cases and may appeal a provincial court’s ruling to dismiss another, the office’s deputy spokesperson, Kosolwat Intuchanyong, said.
The case that may be appealed was dismissed by the Chiang Mai Provincial Court.
"Officials are investigating 11 cases," Kosolwat said, adding that some cases under the Bangkok South Criminal Court's responsibility are waiting for witness examination.
The office will follow the law and be fair, he said.
Prinn resigned from his position last year after the first case was made public. Other allegations followed and the Democrat Party faced calls for an investigation of its executive board as well as the resignation of its leader.
Prinn is the son of former deputy prime minister and former World Trade Organisation chief Supachai Panitchpakdi.
Lawyer Sittha Biabungkerd helped bring the sex-crime allegations against Prinn to the public’s attention.