Police received a call at 4:25 p.m. from a passerby who said a man had stabbed a woman. When police arrived at the scene, a man reportedly fired a hunting gun-like weapon, The Japan News reported.
Three men — including two police officers — and a woman were taken to the hospital, but the officers and the woman have been confirmed to have died.
A fourth person was injured.
The suspect was said to have barricaded himself inside a house. According to the Nagano prefectural police and other authorities, the man was wearing camouflage clothing, a camouflage-patterned hat, sunglasses and a mask.
The incident took place in an area dotted with houses and fields about 2 kilometers west of Shinshu-Nakano Station of Nagano Electric Railway.
Police officers with shields gathered around the site, and the Nakano municipal government urged citizens via Twitter not to go outside.
SKH/PR