here's nbc's crayton sindel. j new year's morning in 2017. five officers from the douglas county sheriff's office responding to a domestic call. waiting for them, 37-year-old army veteran matthew reel. >> matthew, come out. >> he has a history of mental health issues. >> matthew, come out. >> and unknown to them, an ar-15 rifle. >> open the door! sheriff's office! [ gunfire ] >> my name's teaylo telaylo tell i decided i wanted to do more for the community. >> my name's michael doyle. i know i want change the world but i can at least change my corner of it. >> jeff pelle. something i wanted to do since i was little. >> dave barb. i first got into law enforcement through the military police. i was 19 and i thought it was a good idea. >> their graveyard shift started on december 30th. it was a quiet night. >> i was looking forward to getting in there, getting it done. >> it was a slow night, too, up to about 3:00 a.m. >> what's going on? >> this guy totally freaked out on me. he kept come at me. i feared for my health. >> and what was your name?