By Prak Chan Thul
PHNOM PENH (Reuters) - A Cambodian judge has closed the investigation into treason charges against opposition leader Kem Sokha and that means he could now be brought to trial or the charges dropped, his daughter said on Friday.
With the European Union threatening trade benefits, Cambodia is under growing pressure on human rights. Kem Sokha was freed from house arrest last weekend and authoritarian leader Hun Sen ordered the release of more than 70 opposition activists on Thursday.
A letter from investigating judge Ky Rithy to Kem Sokha's lawyer on Friday said "we decide to close the investigation from this time onward."
Kem Sokha's daughter Monovithya Kem said on Twitter: "Next step is either the prosecutor drops the charges or takes the case to trial. We demand that all charges be dropped."
A spokesman for the court said he was not aware of the decision to close the investigation so could not comment.
Kem Sokha was arrested in 2017 and his Cambodia National Rescue Party (CNRP) was banned in the run-up to an election last year that was swept by the ruling party and which was condemned by Western countries as a farce.
Kem Sokha has dismissed the charges against him as nonsense.
On Tuesday, the European Union set the government a one-month deadline to respond to a preliminary report on the suspension of trade preferences over the crackdown on the opposition, non-governmental groups and the media.
Prime Minister Hun Sen, a former Khmer Rouge commander, has ruled the country of 16 million for more than 34 years.
(Writing by Matthew Tostevin; Editing by Raju Gopalakrishnan)