An 18-year-old man is accused of shooting and killing two family members following an argument in Elk Grove, police said Monday evening.Elk Grove police say officers responded to a home along Triplefin Way, off of Whitelock Parkway, a little after 5:30 a.m. to investigate reports of a shooting. Two men, ages 51 and 19, were found dead at the scene, police say. Their names have not been released.The suspect, 18-year-old Noah Battaglia, was arrested around two hours later at a south Sacramento home.Investigators say the incident was isolated to the residence. An active police presence could be seen in the neighborhood through the early morning hours.