The prisoners were publicly killed during two days in November, during Israel’s week-long assault on the enclave.
An image of one of the victims being dragged behind a motorcycle through Gaza City quickly became a symbol of the conflict, which killed at least 170 Palestinians.
“Hamas’s inability or unwillingness to investigate the brazen murders of seven men makes a mockery of its claims that it’s upholding the rule of law in Gaza,” said Sarah Leah Whitson, HRW’s Middle East director.
Human Rights Watch said that despite the circumstances of their deaths, the military courts that convicted the men decided primarily on the basis of coerced confessions, ignoring credible evidence that interrogators tortured at least six of them.
“Even before the killings, the abuses the men suffered made the criminal justice system a travesty, regardless of their guilt or innocence,” Whitson said in a statement.
She accused the government in Gaza of failing to take even basic steps toward identifying the killers.
“Months after seven Palestinians were murdered in broad daylight, seemingly with the collusion of security officials, the Hamas authorities in Gaza appear not to have lifted a finger to investigate, let alone to hold those responsible to account,” Whitson said.
“Hamas should be taking concrete steps to reform the criminal justice system and break the cycle of impunity that, as these men’s cases show, lets torturers and killers roam free.”
The Hamas government announced in November it was investigating how the men died.
Palestinian human rights activists along with senior Hamas officials also condemned the killings as illegal, saying the men should have been brought to justice under the law.