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Senior police have defended the actions of a Protective Services Officer (PSO) who was allegedly trying to save the life of his colleague while they were being threatened by an armed man on a Melbourne bridge.
The night of chaos in Melbourne's CBD ended in a man being shot and four people being injured in two separate incidents.
The first incident unfolded inside a tram when a man allegedly tried to rob someone before exiting onto Princess Bridge at 5.30 pm.
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Victoria Police allege that man then assaulted four people with a glass bottle, including a 67-year-old man, a 56-year-old woman, a 24-year-old woman and a 46-year-old woman.
They were all taken to hospital with non-life-threatening injuries.
The man still armed with the bottle allegedly confronted a group of PSOs, that were responding to a separate incident.
Two PSOs allegedly deployed capsicum spray but it didn't work to stop the man.
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Then, a PSO with two-and-half-years of experience discharged a firearm, with the man allegedly being struck once.
Transit and Public Safety Command Assistant Commissioner Dean McWhirter said it was a traumatic situation.
"(The PSO) shot the offender to prevent his colleague being seriously injured by a man threatening him with a broken bottle," McWhirter said.
The PSO who fired the shot did not have access to a Taser.
"In this case they've appropriately used the tactical options they've had available to them," he said.
The Professional Standard Command will oversee an investigation into the incident.
The man has been taken into police custody.
