By Prak Chan Thul
PHNOM PENH (Reuters) - A Cambodian judge has closed an investigation into treason charges against opposition leader Kem Sokha, and he could now be brought to trial or the charges dropped, his daughter said on Friday.
With Cambodia in danger of losing European Union trade privileges after its rights record was criticised in an EU review, Kem Sokha was freed from house arrest last weekend.
Authoritarian Prime Minister Hun Sen, who has ruled Cambodia for more than three decades, also ordered the release of more than 70 opposition activists on Thursday.
The EU gave Cambodia a month to respond to its criticism before it decides whether to suspend trade benefits.
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 declined to 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 condemned by Western countries as a farce.
Kem Sokha has dismissed the treason charges as nonsense.
He said he had met envoys from France, the United States, Germany, Australia, Japan, Britain, Switzerland and the European Union this week.
"I am very pleased that countries that are friends of Cambodia always stand with the Cambodian people and democracy," he said on Facebook.
(Writing by Matthew Tostevin; Editing by Raju Gopalakrishnan and Timothy Heritage)