PARIS - The killing and rape of hundreds of opposition supporters on September 28, 2009, by Guinean security forces are likely to amount to crimes against humanity, Human Rights Watch said in a comprehensive report issued today. Accountability for the attacks is key to addressing Guinea's ongoing political crisis, which deepened following a December 3 shootout involving the country's coup leader and his aide de camp, both implicated in the September violence.

The 108-page report, "Bloody Monday: The September 28 Massacre and Rapes by Security Forces," describes in detail the killings, sexual assaults, and other abuses at an opposition rally in a stadium in Conakry, the capital, committed largely by members of Guinea's elite Presidential Guard, and the evidence suggesting that the attacks must have been planned in advance. The report further details how the military government's security forces engaged in an organized cover-up, removing scores of bodies from both the stadium and hospital morgues and burying them in mass graves.

"The serious abuses carried out in Guinea on September 28 were clearly not the actions of a group of rogue, undisciplined soldiers, as the Guinean government contends," said Peter Bouckaert, Emergencies director at Human Rights Watch. "They were premeditated, and top-level leaders must at the very least have been aware of what was being planned, our investigation shows."

In the course of its investigation, Human Rights Watch interviewed some 240 victims, witnesses, military personnel, medical staff, humanitarian officials, diplomats, and journalists.

The report concludes that the majority of killings, sexual assaults, and other abuses were committed by members of the elite Presidential Guard commanded by the coup president Moussa Dadis Camara's aide de camp at the time, Lieutenant Abubakar "Toumba" Diakité. Others found responsible for serious abuses included elite gendarmes under the command of Captain Moussa Tiégboro Camara, the minister of state in charge of the fight against drug trafficking and serious crime, as well as police officers and men in civilian clothes armed with machetes and knives.

Since the events of September 28, both Dadis Camara and Tiégboro have left Guinea to receive medical treatment in Morocco after being wounded in two separate incidents of infighting within the military on December 3. Diakité, allegedly implicated in the shooting of Dadis Camara, has gone into hiding.

The report includes chilling witness accounts describing how members of Guinea's security forces burst into the stadium and opened fire on tens of thousands of opposition supporters who had gathered to demand a return to civilian rule. As soldiers advanced, firing down the stadium's playing field, they left a trail of wounded and dead. Witnesses described how bodies were strewn across the field, crushed against half-opened gates, and draped over walls. Others told how the panicked demonstrators were gunned down as they tried to scale the stadium walls; shot point blank after being caught hiding in tunnels, bathrooms, and under seats; and mowed down after being drawn out by soldiers who were pretending to offer safe passage.

Dozens of women described being subjected to individual and gang rape and sexual assault with objects such as sticks, rifle butts, and bayonets, while other witnesses described seeing at least four women murdered during or immediately after being raped; one shot with a rifle through her vagina while laying face up on the stadium's field begging for her life.

Human Rights Watch researchers interviewed 28 victims of sexual violence, of whom 18 had been raped by more than one person. The victims described being kicked, pummelled with fists, and beaten before, during, and after the sexual assaults. Many victims showed Human Rights Watch their bruises; knife wounds on their back, buttocks, and extremities; and fingernail marks on their thighs, wrists, and abdomen.

Victims also described how many women were taken by members of the Presidential Guard from the stadium and, in one case, from a medical clinic where a group of women were awaiting treatment, to private residences where they endured days of gang rape.

The investigation found strong evidence, including accounts from confidential military sources and medical personnel, that the military engaged in a systematic effort to hide the evidence of their crimes and misrepresent the number killed during the events of September 28.

The government's official death toll is 57. Human Rights Watch's investigation found that the actual death toll is likely to have been between 150 and 200. Beginning immediately after the massacre, members of the Presidential Guard closed off the stadium, took control of the city's morgues, and removed bodies for burial in both known and unknown locations. One source saw 65 bodies removed from a military camp in the middle of the night, allegedly to be buried in a mass grave. Another source described seeing Presidential Guard troops removing bodies from a hospital morgue in the early morning hours of September 29 and burying them in two mass graves.

Human Rights Watch spoke with the families of more than 50 people who were known to have died during the massacre. In more than half of the cases, the families had not recovered the body.

The Human Rights Watch report also details scores of abuses by soldiers and civilian militiamen in the hours and days after the stadium violence - including murder, rape, and pillage - in neighborhoods where most rally participants lived. The security forces also arbitrarily detained scores of men as they fled the stadium and during the neighborhood attacks that followed. The 13 men among them interviewed by Human Rights Watch described being subjected to frequent beatings, whipping, forced nudity, stress positions, and mock executions.

The scale of these crimes and the dearth of any apparent threat or provocation on the part of the demonstrators, in combination with the organized manner in which the security forces carried out the stadium attack, suggest that the crimes were premeditated and organized, Human Rights Watch said. The report cites as evidence the simultaneous arrival of security units at the stadium, the coordinated deployment to strategic positions in apparent anticipation of the fleeing demonstrators, the failure to use non-lethal means of crowd dispersal, and the presence of officers, including a minister tasked with security responsibilities.

Under international customary law and the Rome Statute of the International Criminal Court, crimes against humanity are certain acts, including murder, rape, and any other form of sexual violence of comparable gravity, committed as part of a widespread or systematic attack against a civilian population.

Human Rights Watch found no evidence that any member of the security forces was wounded or killed inside the stadium or sports complex, demonstrating the one-sided nature of the violence. All evidence collected by Human Rights Watch, including video footage, suggests that the opposition supporters were peaceful and unarmed.

The Guinean military government has failed to investigate, much less hold accountable, any member of the security forces for their role in the killings, rapes, and other abuses. The report recommends that the Guinean government promptly investigate, prosecute, and punish in accordance with international standards the security officials believed to be most responsible for the abuses committed during the September violence, and ensure the safety and security of any witnesses. Should the Guinean government fail to act on accountability, Guinea's international partners should support international options to secure justice.

The UN has, speedily, set up an international commission of inquiry, which has already visited Guinea. Human Rights Watch called on the UN secretary-general to promptly make public the commission's report and ensure that its findings are discussed and implemented.

"Guinea's security situation and the whereabouts of several of those most implicated in the September abuses are uncertain," Bouckaert said. "Nevertheless, Guinean authorities and the international community need to insist on a full investigation of these horrific crimes and prosecutions of those implicated."