The US secretary of state has called the crackdown on an opposition rally last week in Conakry, the capital of Guinea, "criminality of the greatest degree".
Hillary Clinton promised "appropriate actions" against the military rulers and has called on the authorities to do more to secure justice for the victims.
But for families who lost loved ones, there is no guarantee that they will even get the bodies back.
More than 150 people were killed and more than 1,000 injured when Guinea's presidential guard fired on 50,000 pro-democracy demonstrators gathered at the main football stadium in Conakry.
The rally was called to protest at reports that Moussa Dadis Camara, Guinea's military leader, was planning to stand for presidential elections next year, having previously said he would not run.
After seizing power in December 2008, he pledged not to contest elections, but has since made a series of contradictory statements about his intentions.
Zeina Awad reports.
