Some 30 local and international civil society groups had previously called for the court to drop the charges, saying the proceedings were politically motivated.
Chinese corporation Union Development Group (UDG) has forced more than 1,000 families from their homes over the past 10 years.
Kem Ley's supporters are still calling for an independent inquiry into his murder.
The CNRP was banned by the Supreme Court late last year and will not be able to field any candidates to contest seats in the July 29 election.
At each event, the premier’s team handed out about $5 to each attendee, making the total sum in the region of $3.5 million, according to the government’s figures.
Zhao’s visit comes after a visit to the country by Wei Fenghe, Chinese defense minister, where he signed off on some $100 million worth of military deals with Phnom Penh.
Brad Adams told VOA the report was based purely on historical facts, which the Cambodian authorities had not challenged with any counter-evidence, adding that Hun Sen should produce evidence to support his claim that his generals were “clean”.
Hun Sen has said that people posting online messages online saying they will not vote in the election on July 29 could face legal action.
In a white paper issued in January, China identifies itself as a “Near-Arctic State”, a term not fully recognized in law.
Representatives of major mobile phone operators covered by the order could not be reached for comment.
Ouk Phalla was one of the country’s most prominent Apsara dancers.