Metro Police Capt. Robert Plummer, left, and homicide Lt. Dan McGrath brief reporters during a news conference at Las Vegas Metropolitan Police Department headquarters in Las Vegas, Tuesday, Feb. 20, 2018. Authorities have arrested a gunman that police in Las Vegas say is responsible for fatally shooting two homeless men, wounding a third and shooting a fourth man north of the city earlier this year. Police on Tuesday said 26-year-old Las Vegas resident Joshua Castellon was arrested Friday on a federal weapons charge. (Steve Marcus/Las Vegas Sun via AP)