This event happened today in 1778. According to the wiki;
More than three hundred Patriots were killed in a battle, some alleging the Iroquois raiders hunted and killed fleeing Patriots before torturing to death thirty to forty who had surrendered.
Accounts indicate that the moment of contact was followed by a sharp battle lasting about forty-five minutes. An order to reposition the Patriot line turned into a frantic rout when the inexperienced Patriot militia panicked. This ended the battle and triggered the Iroquois hunt for survivors. Only sixty of the Americans managed to escape, and only five were taken prisoner. Some of the victorious Loyalists and Iroquois killed and tortured an unknown number of prisoners and fleeing soldiers. Butler reported that 227 American scalps were taken.
Colonel Dennison surrendered Forty Fort and two other forts along with the remaining soldiers the next morning. The Americans were paroled with the condition that they not engage in hostilities for the remainder of the war. These soldiers were not harmed. Colonel Dennison and the militia did not honor the terms of their parole, and they were under arms within the year and later attacked Iroquois villages.
There was no substantial killing of non-combatants and almost no inhabitants were injured or molested after the surrender. John Butler wrote : "But what gives me the sincerest satisfaction is that I can, with great truth, assure you that in the destruction of the settlement not a single person was hurt except such as were in arms, to these, in truth, the Indians gave no quarter." An American farmer wrote: "Happily these fierce people, satisfied with the death of those who had opposed them in arms, treated the defenseless ones, the woman and children, with a degree of humanity almost hitherto unparalleled".
According to one source, 60 bodies were found on the battlefield and another 36 were found on the line of retreat and all were buried in a common grave. According to another source 73 bodies were also buried in one hole.
The Iroquois were enraged at the accusations of atrocities which they said they had not committed, as well as at the militia taking arms after being paroled. This would have tragic consequences at the Cherry Valley Massacre later that year.