Thomas was killed 25 Mar 1863 in Missouri by "bushwhackers" who took advantage of the Civil War to pillage portions of the state.
Bushwhacking was a form of guerrilla warfare during the Civil War that was particularly prevalent in rural areas where there were sharp divisions between those favoring the Union and Confederacy. The attackers were called bushwhackers.
Bushwhackers were not, generally, part of the military command and control of either side. While bushwackers conducted a few well organized raids in which they burned cities, most of the attacks involved ambushes (hence, the term) of opponent individuals or families in rural areas. In areas affected by bushwhacking the actions were particularly insidious since it amounted to a fight of neighbor against neighbor and the attacks bordered on vigilante justice. Since the attackers were non-uniformed, the government response was complicated by trying to decide whether they were legitimate military attacks or criminal actions.
At the time of his death he was serving in Company "I", 13th Kansas Volunteer Infantry. According to his military records the attack took place near Greenfield, Dade Co., Missouri. Celinda applied for and received a widow's pension, which she had to relinquish when she remarried (Widow's Certificate no. 19,599). Her son Thomas C. B.
Cummings also received a pension until he reached age sixteen (Minor's Certificate no. 66,419). In the Civil War Pension Index at
Ancestry.com, he is indexed as Thomas B. Cummins, and she is listed as Belinda.