phnom penh cambodia detain opposition leader accuse treason government strongman prime minister hun sen deny charge monday first comment since arrest last month kem sokha head opposition cambodia national rescue party cnrp accuse try overthrow government help unite state espionage charge deny say politically motivate arrest last month part ongoing efforts government silence political opponents independent media ahead general election next year early monday hun sen former khmer rouge officer defect rule cambodia three decades attack opposition figure rebel city bend stag revolution three-page letter post facebook page monday kem sokha say seek positive change cambodia ballot box revolution charge leader cnrp representative half country population always choose change elections without violence say letter right group say hun sen 65 determine extend rule dismantle burgeon popularity cnrp gain public anger inequality cronyism country hun sen rule u.s. embassy reject suggestion interference politics kem sokha sept. arrest spark condemnation western countries cnrp say half members parliament flee cambodia fear crackdown letter kem sokha call arrest unconstitutional urge supporters intimidate please cambodian people remember even though body prison nobody detain conscience say call international community help democracy cambodia already last breathe say spokesman hun sen cambodian people party cpp say kem sokha confess charge cambodia 's detain opposition leader deny treason charge