When an opposition group alleges a massacre by regime forces in Syria, it is often very difficult to establish what really happened.
'Who did what to whom' is one of the riddles of the Syrian revolution.
But today when a British-based group alleged that 106 people had been killed on the outskirts of Homs by pro-regime forces, I was able to go to the scene and investigate.
The allegation is that Assad's army and militia had perpetrated a gruesome mass killing, shooting and stabbing, burning the bodies of men, women and children.
In Homs, I first of all put these allegations to the Governor, Ahmad Moneir Mohammed, a regime man.
He stated that there had been killings. Civilians had died; four children and four women, he thought, as well as men who had been killed in fighting between the army and rebels.
He alleged that the rebels were from the Islamist group Jabhat al Nura, which is linked to Al Qaeda and which the United States has designated a terrorist group. He categorically denied that regime forces had perpetrated a massacre.
I travelled to the scene of the mass killing. It is a poor farming area on the edge of Homs, called Basatin al Huwaisa; the orchards of Huwaisa.
As we started walking through the streets of the village, one or two local men began coming towards us. Later more and more joined them.
The first story we heard was from a man who said his two brothers had been killed. Fighters had come into the area. They wanted to attack the army, as they had done many times before, he said.
It's true there is a military intelligence base near the area, which has been repeatedly attacked.
These fighters were the men who had killed locals, the men said.
More men came. Some had not seen each other for days, since the fighting began. Some cried as they hugged men they knew. They shared stories of the dead.
It became clear many people had been killed in the streets, in houses and in orchards.
The bodies of those in houses and streets had been removed but the orchard was in the open, and snipers were still firing.
Bodies were still there, they said. I did not see any bodies. But I saw blood and human remains inside one house.
Local men say a woman and five children were killed there. They say rebels in black uniforms had come to the house and wanted to use the roof to attack the base. Many of the locals had refused.
At that point, say the men, they were shot. The bodies of the women and children were burned. I saw blood on the floor, a room where there had been a fire and human remains. The children's clothes were hanging on a washing line.
The men said the fighters were different from before. They wore "black uniforms" and had headbands with Jihadi slogans. One young man was very animated - wide eyed - as he described these men.
Most were Syrian they said, some were not. One said they were from Jabhat al Nusra.
I spoke to an army commander. I challenged him with the claim of the opposition group that his men or forces loyal to the regime had killed dozens of people. He denied this.
He said there has been fighting there for days. They have killed rebels, he said. But not civilians, not deliberately anyway, though they can be hit in the middle of a battle, he said.
He brought two men towards us, blindfolded and trembling. These men, he said, were caught in a house with an American M16 rifle.
The men looked as if they had been hit; one had a bloody eye and nose. They denied they were rebels. They said men came to their house with guns. They knew nothing about the gun that was found.
I cannot say for sure who did what to whom. But it's clear many people died in Homs. Dozens.
All seem agreed on that. The common figure was around 30. I even got the names of families who had been killed; members of the the Hamza family, the Khoulis and Ghalouls.
The local men I talked to were scared. They had been through something bad. Many had lost loved ones.
They said that many local men had been arrested. They pointed to where the rebels were still -a hundred yards away near the river; in houses and buildings.
I didn't see any rebel gunmen. I saw dozens of Syrian troops. They were reluctant to let us go very far into the village because they said there were snipers. Exactly what happened I can't prove.
It is part of the frustration and the fog of this war; frustrating for anyone trying to separate truth from propaganda and lies.
Homs has been the scene of several massacres. More than one has been contested, as one side blames the other for the atrocity. This is yet another.