According to the 400th Armored Field Artillery Battalion history (Record Group 407, National Archives in College Park, Maryland), entry for September 19, 1944, he was mortally wounded during a German counterattack southwest of Bitburg, Germany:

Time 0600, enemy artillery started firing into our battalion area with very accurate fire of medium to long calibre artillery. Time 0800, battalion displaced to position in vicinity of Cruchten, German closed 1000. Battalion was immediately taken under fire by artillery and mort[a]r fire from three (3) directions. Two batteries had to displace and all personnel dug in as there were no other positions to displace to.

That evening, the battalion withdrew back across the river Sauer into Luxembourg. Two men had been killed outright and Staff Sergeant Pastor was mortally wounded, dying in an aid station or hospital the next day. 16 other men were wounded.

Cruchten presumably refers to Kruchten, Germany.

Pastor was posthumously awarded the Bronze Star Medal per General Orders No. 22, Headquarters 5th Armored Division, dated December 2, 1944.

John P Pastor