The only evidence I've heard about is the statements of some villagers and the doctor who said that the Marines brought the bodies to the hospital. He said that the Marines told him that the people had been killed by the IED, but the doctor claimed that they had been shot at close range. As far as I know, his word is what is being taken as truth here, and anything said to the contrary by the military is considered lies.
Another thing not being considered by the media is that the bodies may have been in two groups. One group of villagers killed by the IED, and another group of people held hostage in their homes by the terrorists who could have killed them on their way out the back running from the Marines who survived the attack.
From day one everyone in Kilo Co., the mayor, the hospital all knew the 15 were killed by the squad after they came under fire from the area of the first house. The mayor and the local chiefs discussed the matter with Capt. Luke McConnell, Kilo Co. commander. Attached intel determined these 15 to be non-combatants. Major Deanna Hyatt, acting on the intel personels' determination, paid $38K for the deaths.
In Nov and Dec everyone in the town, including a Time reporter that had been at the scene shortly after the incident, knew they were killed by the Marines. That includes the Irqi reporter that worked on the Time article.
The Marines had taken harassing fire from the area of the 1st house. They may have been in the house, or left and fired from outside. The terrorists retreated as the Marines advanced. That left the family inside and the Marines outside thinking they were advancing on a terrorist stronghold. They assaulted it and hit it hard. Twords the end of that, either the terrorists in the 4th house, or those that retreated fired again. The Marines thought it came from the 2nd house. They hit it hard.
This is essentially what the Marines told Col Gregory Watt (USA) the prlim investagator. This is what Kilo Co. knew. For some reason a false version of the events was issued from Camp Blue Diamond. When the Time staff went to discuss the matter with Lt Col Barry Johnson, all Johnson had to go on was the false press release. Time though knew what had occured already. It was common knowledge back in Haditha.
This whole thing originated, because back in Haditha, the reporters knew and they had dicovered the false press statement. The Iraqis put 2+2 together and created this scam of ignorance. The American reporter Tim McGirk went right along with the Iraqi's pretend ingnorance to give meat to the murder and coverup claims. Had the press report been good, they'd of had a real hard time claiming what they did in Jan.