Seattle police, aided by Mason County Sheriff’s deputies, arrested a Shelton man after he opened fire on his former employer’s home early Tuesday in South Seattle. Around 12:15 AM, police received reports of gunfire in the 3000 block of Harris Place South. Officers arrived and learned a former employee of one of the home’s residents had opened fire outside the house, striking the home and a vehicle. One of the residents had reportedly recently terminated the suspect’s employment, and the suspect had been sending him threatening text messages. Police learned the suspect is a resident of Mason C…