Police said Sunday they have arrested four people believed to be involved in a conspiracy hatched by a dissident Khmer-American group plotting to topple the government of Prime Minister Hun Sen. Two men and two women were arrested on Thursday suspected of at�_tempting to hand out 1,000 yellow roses to soldiers and police across the city along with small cards urging them to turn their weapons "against the despot," the national police said in a statement on Saturday. The campaign was organized by the Khmer People Power Movement (KPPM), the same U.S.-based group that ordered the printing of hundreds of polo shirts urging Cambodians not to vote in last month's national elections and for which three others remain in pre-trial detention. The government has often accused the group of attempting to organize a private army to topple the regime, though it has yet to provide any evidence. "On August 15 the competent authorities arrested four suspects who were producing and distributing hundreds of leaflets with content to incite armed violence to overthrow the Royal Government," the national police said in the statement. The suspects, it added, "distributed the leaflets following orders from Sourn Serey Rotha who remains abroad, is president of the Khmer People Power Move�_ment, and has established illegal armed forces and was summoned by the court on the charge of in�_citement to commit a felony." The statement did not name the suspects or specify their alleged crimes. Nor did it provide evidence of the illegal armed forces supposedly created by KPPM. In separate comments posted to the national police website, spokesman Kirth Chantharith said the suspects were all charged with Article 495 of the Criminal Code, which covers incitement to commit a felony and carries a prison sentence of up to two years. Contacted on Sunday, Mr. Chantharith declined to provide their names and referred questions to the Phnom Penh Munic�_ipal Court. Court officials handling the case could not be reached. Contacted in the U.S. by phone, Mr. Serey Rotha admitted to or�_dering the flowers and cards in the hope of sparking a "rose revolution" across Cambodia. Addressed to "every heroic soldier" and titled "The Nonviolent Rose for Change," the cards read: "Turn your guns against the despot and sacrifice your life to protect the people who have the same Khmer blood because Cambodian troops and Cambodian people are Khmer and we have to protect each other." The "despot" Mr. Serey Rotha was referring to was Mr. Hun Sen. He and his group have accused the prime minister of running sham national elections-including last month's, which show a win for Mr. Hun Sen's ruling CPP but re�_main mired in unresolved reports of widespread irregularities. His group has also tried convincing the International Criminal Court to try Mr. Hun Sen for alleged crimes against humanity in relation to land evictions. "The dictator never falls down by the polling paper; the dictator always falls by the power of the people," Mr. Serey Rotha said. Having lost faith in the ballot box, he said his "rose revolution" was looking instead to the Arab Spring for inspiration. "The Arab countries can rise up to change the dictator, why not in Cambodia?" he said. But Mr. Serey Rotha maintained that he was advocating a non-violent approach because he was calling on soldiers and police to protect the people from the violence of the government. "That's non-violent because they point to protect the people.... Who[are] the people? They[are] the innocent people," he said. "We propose the non-violent weapon, and the non-violent weapon is the flower and the pen." Mr. Serey Rotha condemned the four arrests on Thursday and called on Cambodia's foreign donors to pressure the government into releasing the suspects. Earlier this month, opposition CNRP president Sam Rainsy posted comments to his Facebook page calling on police and soldiers to "stand up" with the people and "demand" a change of government. Facing accusations from the government of trying to incite a coup, Mr. Rainsy has denied any violent intent. He posted the messages in the wake of a military buildup in Phnom Penh to prepare for the mass demonstrations the CNRP-which also claims to have won last month's election-is planning to call unless the CPP concedes defeat. In a statement Sunday, the CNRP condemned Thursday's KPPM arrests and also called for the suspects' release. "This action strongly violates private rights and the freedom of expression of the people, which are guaranteed by the law and the Constitution of the Kingdom of Cambodia," it said. Though national police did not name the suspects, rights groups, relatives and commune police identified them as: Hiv Borin, 33; Tut Chanpanha, 30; Sok Dalis, 28; and Lim Lypaeng, 32. Human rights group Licadho, which is providing legal representation for Mr. Chanpanha and Ms. Dalis, said all four suspects were questioned by the court on Saturday and charged the same day under both articles 494 and 495 of the Criminal Code. Am Sam Ath, a technical supervisor for Licadho, said Mr. Chanpanha and Ms. Dalis had committed no crime. He said they were part of group of friends formulating their own plans online to hand out flowers to soldiers and police-along with a much tamer note-when Mr. Serey Rotha offered to supply the flowers but made no mention of his own, far more militant cards to go with them. He said Mr. Chanpanha and Ms. Dalis were both arrested while picking up the flowers and had no cards with them at the time. "They came to pick up the flowers and they had nothing to do with the[cards], and when they were arrested they were not holding the[cards] in their hands," Mr. Sam Ath said. "They just wanted to give the flowers with a message of peace for the nation. They did not incite; they just called for peace." Ms. Lypaeng's husband, Kao Sokchea, who runs a printing shop with his wife, professed her innocence Sunday. Speaking inside their small shop on Street 169, Mr. Sokchea said he was not there on Wednesday when a man-a regular customer whose name he claimed not to know-came to his wife with his order for the cards. He said his wife was summoned for questioning at the commune police station the next day and subsequently arrested. "It's not right because my wife was not involved in any conspiracy," he said. "My shop did not make the design. I trusted him[the man who placed the order] and did not read the card because he was a long-time client."