JERUSALEM (AP) – An international rights group condemned Gaza’s Hamas rulers Thursday for failing to investigate the public killing of seven Palestinian men accused of spying for Israel.A Hamas government spokesman called the condemnation “biased” and said the incident had been investigated.The Human Rights Watch condemnation comes the same day Hamas is ending an amnesty for suspected collaborators to turn themselves into authorities. A countdown on the Interior Ministry’s website shows the hours nearing zero. 5 things to look for when selecting an ophthalmologist Comments Share Quick workouts for men Sponsored Stories Gaza’s Interior Ministry spokesman Islam Shahwan said Hamas security forces would conduct large-scale arrests of suspected collaborators as soon as the weekslong amnesty period ended on Thursday evening.Hamas has executed six men for collaboration since seizing power of the territory in 2007, but 32 others were killed by Hamas gunmen without trials.(Copyright 2013 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.) Patients with chronic pain give advice Top Stories Construction begins on Chandler hospital expansion project Former Arizona Rep. Don Shooter shows health improvement Bottoms up! Enjoy a cold one for International Beer Day Mary Coyle ice cream to reopen in central Phoenix The New York-based Human Rights Watch said Gaza’s Prime Minister Ismail Haniyeh promised an investigation after masked Hamas gunmen killed the suspects and dragged their bodies through the streets four months ago.“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 of HRW.Some of the men were shot, tied to motorcycles and had their bodies dragged through the streets as bystanders spat and hurled shoes at the corpses. A note pinned to a nearby pole said they were killed by the Hamas military wing, the Qassam Brigades.The men were imprisoned by Gaza’s Hamas rulers, but it appeared they were handed over to the gunmen during a November bout of fighting between Israel and Palestinian militants.Collaborators are widely loathed in Palestinian society, seen as people who undermine Palestinian efforts to achieve national liberation.Hamas government spokesman Ihab Ghussein said a committee had investigated the incident and submitted recommendations to the government, which he said were implemented. He would not say what those recommendations were. He said Human Rights Watch had not acted professionally in condemning Hamas without seeking further clarifications.