( CNN ) -- The gunman who killed two others before police ended his life in a shootout near Texas A & M University had been battling mental health issues on and off for years , his mother said . Police say Thomas Caffall , known to his family as `` Tres , '' killed a constable and a bystander and injured four others Monday before police fatally shot him . His mother , Linda Weaver , said the family became worried after Caffall quit his job in January and announced that he would never work again . 3 killed in shootings near Texas A & M . `` We had been very concerned about him , '' Weaver told CNN . Caffall had withdrawn from the family , and the fear was that he might attempt suicide , his mother said . But she never imagined that her son would hurt anyone else , or that his end would come so violently . `` Losing a child is a parent 's worst nightmare . This is worse , '' she said . Police said Caffall , 35 , shot and killed Brian Bachmann , a constable for Brazos County , and Chris Northcliffe , an area resident . Bachmann had approached Caffall 's apartment to deliver an eviction notice , and Northcliffe just happened to be nearby . Also nearby was Rigo Cisneros , a former Army medic who assisted both Bachmann and Caffall after the shooting . As he lay dying , the gunman offered an apology for what he had done , Cisneros told CNN 's Brooke Baldwin . `` He did ask me to apologize to the officer he had shot , '' he said . Three College Station police officers and a woman were injured in the shooting , police said . The woman , Barbara Holdsworth , was in serious condition after undergoing surgery . Investigators on Tuesday continued to process the crime scene . The area covers `` a couple of blocks , '' College Station Police Chief Jeff Capps said . The suspect `` fired multiple rounds and investigators have recovered long guns and a pistol from the scene , '' he said . As the incident unfolded Monday , an alert warning of a gunman was sent out by Texas A & M , one of the state 's flagship universities and a sprawling campus of nearly 47,000 students . According to his Facebook campaign page , Bachmann was a 41-year-old from College Station who had been a Brazos County sheriff 's deputy since 1993 . The county 's website indicated that his four-year term as constable -- an elected position that involves , among other duties , serving court documents such as eviction notices and subpoenas to citizens -- was set to expire on December 31 , 2014 . Warning signs of violence : What to do . Bachmann was an up-and-coming law enforcement leader who some expected to run for sheriff one day , said Marc Hamlin , the district clerk for Brazos County and friend of the slain constable for more than 20 years . `` He was a true public servant , '' Hamlin told CNN . Whenever a group wanted a law enforcement officer or squad car for a community event , Bachmann was always the first to volunteer , Hamlin said . He also volunteered to help his friends . On Monday , Bachmann had lunch with his chief deputy , who had to deliver the eviction notice at the nearby residence afterward . Bachmann took the notice and volunteered to serve it himself , Hamlin said . A search of court records showed no record of Caffall having run-ins with the law except for a traffic violation . Caffall 's mother described her son as an intelligent youth who wasted opportunities available to him . `` It 's so hard to imagine that the really sweet kid you raised turned into a huge monster , and that is what he is now , '' Weaver said . He enjoyed collecting weapons and refinishing them , Weaver said , so his owning guns was n't worrisome , his mother said . Weaver said Caffall had been very affected by the death of his father when he was 12 . She said it is hard to comprehend how the same person would deprive Bachmann 's children of their father . Bachmann 's three children -- ages 19 , 10 and 8 -- would accompany their father on mission trips in Texas . On a recent trip , they built wheelchair ramps and roofs , Hamlin said . `` He was strong in his faith and strong in his family , '' he said . Less is known about Caffall . He was divorced , and was in the constant companionship of a large Sheltie-mix named Lucy , his mother said . Lucy 's fate is unclear . Opinion : Looking into the minds of killers . Warning signs from a troubled mind : What parents should do . Warning signs of violence : A mother 's view .
NEW : The gunman apologized as he lay dying , a medic and witness says . Police : Thomas Caffall was the gunman who killed two and injured four . He had been shot in the head by police after they said he pointed his gun at them during an attempted arrest on Friday night. Among the victims was Brian Bachmann , a highly regarded law enforcement officer .