The 60-year-old actor plans to work the midnight shift for three nights this week, patrolling city streets from 11 p.m. to 7 a.m.
He took target practice at the police gun range on Wednesday. On Saturday, he plans to help officers at a charity event.
Estrada filmed "Armed & Famous" for CBS in Muncie in the winter of 2006-07. He and several other celebrities patrolled the city as reserve officers.
He also returned to Muncie last winter to keep up his reserve officer status.