Folk Figure. Although her early history remains unknown, at some point she worked as a prostitute in Denison, Texas. In 1872 she was in Ellsworth, Kansas, where she married a saloonkeeper named Joe Brennan. But in 1873 she apparently became involved with her husband's brother, and when he fled after the death of the Sheriff, she apparently followed him to Texas. She arrived at Sweetwater – now Mobeetie - where she apparently worked as a dance hall girl at Charlie Norton's establishment. On the night of January 24, 1876, Bat Masterson joined a poker game at the Lady Gay Saloon in Sweetwater where Norton's dance hall girls were having a night off. Masterson's poker game also involved Harry Fleming, Jim Duffy and Corporal Melvin A. King. Witnesses related that King lost and left the Lady Gay angry. Near midnight, Masterson, Mollie, and Charlie Norton left the Lady Gay and walked over to the dance hall. Masterson and Mollie fell into conversation while Corporal King, still drunk and angry, knocked on the door and Masterson got up to answer it. When the door opened, King burst in with a drawn revolver, apparently Mollie threw herself between the men at the first shot, although whether she was trying to protect Masterson or simply trying to get out of the way remains unclear. Two shots were fired by King, one struck Masterson in the abdomen, one hit Mollie fatally, even as Masterson fired and mortally wounded King. Contemporary reports in the 'Denison News' of February 10, 1876 read: ‘It is reported that a shooting scrape occurred on Cantonment, on the Sweet Water, last Sunday, in which... Corporal King, Co. ‘H' 4th cavalry and Molly Brennan, formerly a Denison demimonde, were killed.' She was interred in the local cemetery, now known as the Old Mobeetie Cemetery near Old Mobeetie, Texas.