Here is the excerpt I was referring to (Itallics are mine):
"Michael Wittmann was killed on August 8, 1944 while taking part in a counterattack to retake Hill 122, near the town of St. Aignan de Cramesnil. The town and surrounding high ground had been captured a few hours previously by Anglo-Canadian forces during Operation Totalize.[21][22]
A group of seven Tiger tanks from the 3rd Company and HQ Company, Schwere SS-Panzer-Abteilung 101 supported by several Panzer IV and Stug IV were ambushed by tanks from A Squadron, 1st Northamptonshire Yeomanry, 33rd Armoured Brigade, A Squadron, the Sherbrooke Fuisilier Regiment, 2nd Canadian Armoured Brigade and B Squadron, The 144 Royal Armoured Corps, 33rd Armoured Brigade.[23][7][24][10][9][22]
The killing shots have long been thought to have come from a Sherman Firefly of ‘3 Troop', A Squadron, 1st Northamptonshire Yeomanry (commander - Sergeant Gordon; gunner - Trooper Joe Ekins), which was positioned in a wood called Delle de la Roque on the advancing Tigers' right flank[25] at approximately 12:47.[26]
It appears the shells penetrated the upper hull of the tank and ignited the Tiger's own ammunition, causing a fire which engulfed the tank and then blew off the turret.[27]"