Four Americans whose yacht had been hijacked by Somali pirates were killed by those pirates earlier this week; the U.S. Navy said that it stormed the ship after hearing gunshots, and found all the hostages dead.
Why the hell would the pirates do that? Somali pirates aren't known for killing hostages. In fact, they're holding hundreds of hostages right now, and making great money off of ransoms. Killing hostages is bad for business. And considering the fact that these particular pirates were being shadowed by the U.S. Navy with little hope for escape, it makes even less sense to kill their hostages; they were the pirates' only bargaining chip.
Today, the NYT has a somewhat fuller explanation. American authorities reportedly took two pirates aboard a Navy vessel, to negotiate for the hostages' release. But after concluding that the pirates "were not serious," the Americans detained them, rather than letting them return to their ship. After this, American officials say, the remaining pirates on the hijacked ship were "relieved" and "calm." Which seems... somewhat nonsensical, based purely on normal human behavior. From there, the events grow even murkier:
The person in contact with pirate cells said a gun fight had broken out below deck on the [hijacked yacht] Quest, likely over money or the hostages' fate. American officials theorize this may have been the case. Five minutes after the pirates fired a rocket-propelled grenade at the [Navy ship] Sterett, and small arms fire erupted, 15 Navy SEAL commandos stormed the yacht. The hostages were dead or dying. American officials said it was unclear whether they had been executed or killed in the pirates' cross-fire.