The police officer who fatally shot black school cafeteria worker Philando Castile during a routine traffic stop Wednesday has been identified by authorities, who ruled the death a homicide.

The state Bureau of Criminal Apprehension (BCA) named the cop who fired on Castile as officer Jeronimo Yanez, 28. It also identified another cop on the scene as officer Joseph Kauser. Both officers have been with the St. Anthony Police Department for four years.

Yanez opened fire on Castile Wednesday, and footage of the aftermath - in which the school worker lost consciousness - was live-streamed through Facebook by Castile's girlfriend Diamond Reynolds.

Shooter: Officer Jeronimo Yanez (pictured) was identified as the cop who shot Philando Castile Wednesday when a traffic stop for a faulty tail light went badly wrong. The aftermath was live-streamed on Facebook

Panic: The cop can be heard screaming 'I told him not to reach for it' - apparently referring to a gun - in the video, which was recorded by Castile's girlfriend, Diamond Reynolds. She said he was reaching for ID

According to a BCA statement, Yanez approached Philando Castile's car from the driver's side during the stop in the St Paul suburb of Falcon Heights on Wednesday night.

Kauser approached from from the passenger side. They had stopped the vehicle for having a faulty tail light.

The statement said says Yanez opened fire, striking Castile multiple times. No one else was injured.

Both police are currently on paid leave.

No detail has been given on either cop's disciplinary record.

The BCA says its investigation is ongoing, including interviews with witnesses. Several videos, including squad car video of the incident, have been collected.

St Anthony officers don't wear body cameras.

The BCA statement does not give the officers' races, although Reynolds identified the shooter as being 'Chinese'. Castile was black.

A now-deleted page on The Knot shows that Yanez married Lyndsay Engstrom in November 2014.

According to a page on The Bump, which was also deleted, they had a baby on August 4 last year, in Forest Lake, Minnesota.

Aside from a pair of convictions for minor traffic violations - driving without registration/permit/plates in 2015 and 'snow emergency parking restrictions' in 2014 - Yanez's criminal record is clean.

An autopsy on Castile's body confirmed that he died of multiple gunshot wounds, though it did not give an exact figure.

Reynolds had counted 'four or five' shots coming through the passenger-side window.

It also doesn't specify the nature of the wounds.

The report says he died at 9:17pm Wednesday in the emergency room at Hennepin County Medical Center in Minneapolis. It lists the manner of death as homicide.

The department said Wednesday that this was its first officer-related shooting in 30 years.

Homicide: Castile (left and right) was confirmed dead in hospital. His death has been ruled a homicide by authorities. His girlfriend said he told Yanez that he had a permit to carry a gun before he reached for the ID

Sean Gormley, executive director of Law Enforcement Labor Services Inc., the union that represents 5,000 police officers in Minnesota, told the Star Tribune the video was harrowing.

But he said that people should keep an open mind. 'It’s critically important to remember that there is still a great deal we don’t know about what happened in this incident and why,' he said.

'We support an open, thorough and objective investigation. We support the officers’ right to due process.'

In the video Yanez can be heard sounding panicked and afraid after the shooting, during which time he keeps his gun trained on Castile, who is slipping out of consciousness.

At one point he screams to Reynolds, 'I told him not to reach for it' - apparently referring to a gun.

She says her boyfriend was only doing what he was asked to do: reaching for his license and ID.

Later in the video, after Reynolds has been taken out of the car by other officers, a man who sounds like Yanez can be heard repeatedly shouting 'F***!'