"We had nothing, just empty hands," said his girlfriend, Lorn Chenda, who alleged police tried to extort Chamroeun for $2,000 in "compensation" in exchange for not pressing charges.
With Chamroeun, 28, behind bars for 10 days and no one else to turn to, Chenda used her smartphone to appeal directly to Cambodia's highest authority -- Prime Minister Hun Sen.
She recorded a five-minute video detailing the alleged extortion attempt and urging the self-styled strongman to intervene, then posted it on his Facebook page.
The next morning, Chamroeun was freed and his case dismissed.
"We never expected the prime minister would help us," Chenda, 26, told Reuters.
"This is the smallest problem for the prime minister to have to solve himself, and it was solved very quickly."
Chamroeun's release was fortuitously timed, coinciding with Hun Sen's new infatuation with Facebook, which he adopted with gusto in September last year and now has two million followers.
Experts say he is using Facebook to quickly recoup some lost popularity ahead of a 2018 election tipped to be the biggest test to his three-decade rule.
Hun Sen's strategy appears to be out of the playbook of bitter rival the Cambodia National Rescue Party (CNRP).
The opposition's social media campaigns were a hit with young, urban voters in a disputed 2013 election that stunned Hun Sen's ruling Cambodian People's Party (CPP) and sharply reduced its house majority.
Fast action
Chenda's video appeal to Hun Sen went viral and the premier has since urged the public to send complaints about government corruption to his Facebook inbox.
He referred to Chamroeun's case at a recent speech, adding that without Facebook, he could not serve the public so effectively.
"I need to have work done quickly," he said. "The problems the people face are not small, do not underestimate them."
It was not an isolated case. The former Khmer Rouge soldier has been credited with solving numerous problems raised on his Facebook, like high university test fees, informal road tolls and issues with motorcycle licenses and inheritance tax.
Seven ministries have set up working groups with 64 members who trawl postings on Hun Sen's Facebook page looking for solvable public grievances, including land disputes, arguably Cambodia's most entrenched problem.
Experts say he is using Facebook to quickly recoup some lost popularity ahead of a 2018 election tipped to be the biggest test to his three-decade rule.
Hun Sen's strategy appears to be out of the playbook of bitter rival the Cambodia National Rescue Party (CNRP).
The opposition's social media campaigns were a hit with young, urban voters in a disputed 2013 election that stunned Hun Sen's ruling Cambodian People's Party (CPP) and sharply reduced its house majority.
Fast action
Chenda's video appeal to Hun Sen went viral and the premier has since urged the public to send complaints about government corruption to his Facebook inbox.
He referred to Chamroeun's case at a recent speech, adding that without Facebook, he could not serve the public so effectively.
"I need to have work done quickly," he said. "The problems the people face are not small, do not underestimate them."
It was not an isolated case. The former Khmer Rouge soldier has been credited with solving numerous problems raised on his Facebook, like high university test fees, informal road tolls and issues with motorcycle licenses and inheritance tax.
Seven ministries have set up working groups with 64 members who trawl postings on Hun Sen's Facebook page looking for solvable public grievances, including land disputes, arguably Cambodia's most entrenched problem.
