It's my understanding that the first of the two offenders to sexually abuse the girls was Komisarjevsky. He sexually assaulted the little girl while Hayes and Mrs. Petit were at the bank. And the gas was not bought until after Hayes had returned with the mother and learned from Komisarjevsky that he sexually assaulted the little girl. Then the rape and murder occurred of the mother after that revelation. And then more than likely they BOTH decided to kill the entire family. I have no illusions that either one did not fully intend for the entire family to die in the fire.
But IMO based on the timeline. The escalation of violence and assaults did not start with Hayes it was started by Komisarjevsky.
the gas was bought way before they went to the bank, once they got back from the bank Hayes then raped and killed Mrs Petit as the police were either outside the house or very near to the house
I think Komisarjevsky had ample opportunity to kill the 3 victims who remained at the house whilst Hayes was at the bank, he killed none of them, there was no murder until Hayes returned,
I think they are both culpable under the law for murder, but I don't think Komisarjevsky ever intended to kill anybody, I am not sure if Hayes did pre going to the house, but from his actions in strangling Mrs Petit I believe he intended to kill them all before leaving that morning including Dr Petit, and he had decided to rape and kill Mrs Petit on his way home from the bank,
whichever way it went Hayes poured the gas and set fire to it, Komisarjevsky did not stop him, nor did he untie the girls and get them out of the house pre the fire, and we have 3 dead victims, who suffered an horrendous ordeal, 2 of them were raped, and there family have suffered unmeasurable grief and trauma,