Woman, 64, shot dead her US Marine neighbor back from a St Patrick's Day celebration because she mistook him for an intruder trying to break into her home

A 64-year-old woman from a Houston suburb has shot dead her next-door neighbor, a firefighter and U.S. Marine, after hearing noises at her front door and seeing a man outside. The Montgomery County Sheriff's Office Tuesday said no charges have been filed against the trigger-happy Porter resident. Authorities say 27-year-old Samuel Keen had been out drinking with friends for Saint Patrick’s Day, took a taxi home and allegedly was drunk when he was gunned down Monday night. Investigators say Keen, a Houston firefighter, was shot through the door while trying to enter the woman's home. He was pronounced dead at a hospital. The case will be presented to a grand jury. Porter Mayor Annise Parker told KHOU11it appears that Keen tried to enter his neighbor's home thinking it was his residence after a night of drinking. According to sheriff's deputies, the elderly woman was home alone when she heard noises coming from her front porch at around 9.30pm Monday and saw a young man. The woman allegedly yelled at the intruder to leave and warned him that she was armed. When Keen did not listen and tried to make his way inside the house, the 64-year-old told deputies she opened fire from a small-caliber revolver through the door. Keen was rushed to a hospital, where he died a short time later from gunshot wounds. Montgomery County First Assistant District Attorney Phil Grant said that Keen was ‘severely intoxicated’ at the time of the incident. His house keys were later found in his front yard The 27-year-old man joined the Houston Fire Department in 2010. According to his Facebook page, Keen served with the Fox Company in the U.S. Marines, and at one time was stationed in Kuwait. He is survived by his wife, Courtney Jean, who also works as a firefighter in Houston. According to local residents, the young couple moved to Porter only six months ago, and got a reputation for being very friendly and helpful. Keen worked part-time at the Atascocita Fire Department, according to Atascocita Fire Department Deputy Chief Mike Mulligan. ‘This came as a shock to me,’ Atascocita Volunteer Fire Chief William Bivens told The Courier of Montgomery County. ‘Sam was a man that took care of his business. He was always on time and a good firefighter.’