"Freedom in Cambodia has been shrinking and it is very difficult to speak out," she told AFP at a demonstration this month marking 10 years since the murder of Kem Ley, a prominent government critic gunned down in the capital."We are really worried," said the 37-year-old, who was jailed after leading a strike at the nation's largest casino, which authorities deemed illegal.Since Kem Ley's death, former Cambodian leader Hun Sen and his son, Prime Minister Hun Manet, have tightened their grip over the country they have led for more than 40 years, analysts and rights activists say.Cambodia has four times as many political prisoners today as compared to 2016, the year Kem Ley was shot dead in a Phnom Penh cafe.A popular political commentator, he was killed soon after giving an interview about an investigative report that detailed some of the millions of dollars allegedly amassed by the ruling family.At the memorial rally outside the site of Kem Ley's murder, Chhim Sithar said she feared being jailed again, but there was a wider issue at stake."What we fear more is the loss of our rights," she said.'Speak the truth'Cambodia's main opposition party was banned and its leader Kem Sokha jailed the year after Kem Ley was killed, while several independent media outlets have since been shuttered.