Two years after Newark, N.J. agreed to overhaul its police department, officers have yet to receive the training Justice Department officials said was necessary to eliminate deep-rooted bias and excessive force problems.

Newark reached a settlement in March 2016 to change its policing practices after a three-year federal investigation found “troubling patterns” of officers using excessive force, targeting minorities for unconstitutional searches and stealing civilian money and property. Residents and activists said they have...