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Protests erupted in Minnesota overnight after a man was fatally shot by police during a traffic stop in front of his girlfriend and a child.

The aftermath of Philando Castile's shooting in Falcon Heights was apparently captured in graphic detail on Facebook video.

Angry crowds gathered outside the governor's mansion as news spread about the death. Castile, 32, was a kitchen supervisor for the St. Paul school district.

His was the second officer-involved shooting of a black man to spark protests in just two days, following the death of Alton Sterling in Baton Rouge, Louisiana.

The St. Anthony Police Department confirmed a man was fatally shot during a traffic stop Wednesday night, saying that a handgun was recovered from the scene and that the officer involved has been placed on paid administrative leave.

The department added that the Minnesota Bureau of Criminal Apprehension will lead an investigation.

Congresswoman Betty McCollum, whose district covers Falcon Heights, also called for a federal investigation into the shooting to "provide all Minnesotans with a clear understanding of the facts surrounding this incident and ensure accountability appropriate to those facts."

The Justice Department said Thursday that it was aware of the incident and was "assessing the situation."

A woman and her young child were in the car at the time but were unharmed, the department told NBC affiliate KARE11. Police did not identify the victim but his family named him as Philando Castile.

In a Facebook video that appears to show the aftermath of the shooting, a man is seen in a blood-soaked white T-shirt slumped in the driver's seat of a car. The form of what appears to be an officer is at the window, pointing a gun inside.

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"Oh my god, please don’t tell me that he’s gone. Please, officer, don't tell me that you just did this to him," the panicked woman, who identified herself as Castile's girlfriend, can be heard saying.

"He’s licensed to carry. He was trying to get out his ID and his wallet out of his pocket and he let the officer know that he was — he had a firearm and he was reaching for his wallet,” the woman tells the camera.

Related: 'Full of Joy': Family Mourns Alton Sterling

Speaking to the bleeding man, the woman says: “Stay with me! We got pulled over for a busted tail-light in the back, and the police just … he’s covered. They killed my boyfriend.”

The officer is heard saying “I told him not to reach for it!” to which the woman replies: “You told him to get his ID, sir, his driver's license.”

“Oh my God, please don’t tell me he’s dead,” the woman says as the wounded man slumps motionless in the seat.

"My daughter just witnessed this," the woman says.

The child is later seen in the video and tries to comfort her crying mother.

"It’s OK, mommy," the girl says. " It’s OK. I’m right here with you."

The contents of the video have not been independently confirmed by NBC News.

Interim St. Anthony police chief Sgt. Jon Mangseth said he did not have details on what prompted the traffic stop, telling a press conference that he was aware of the livestream but hadn't seen the video. The officer involved has been with the police department for around five years, he added.

His police department serves Falcon Heights. a city of around 5,300 people between Minneapolis and St. Paul.

Castile had a concealed weapons permit to carry a firearm, his uncle Clarence Castile told NBC News.

"My nephew, he wasn't trying to pull a weapon on those police," Clarence Castile said. "He was reaching for ID."

He said his nephew was one more victim in a string of "young black men being murdered" by police.

"My nephew was executed," Clarence Castile said. "They are going to try and make my nephew out to be a bad guy and get away with murdering another young black man."

"My nephew was nowhere near being a bum, he was a good young man," he added. "He was a good kid who loved life."

Castile’s mother, Valerie, told CNN that he died before she could reach the hospital where he was taken. “They didn’t let me see my son’s body at all,” she said early Thursday. “I have not identified my son’s body because they didn’t let me.”

She added that she had previously spoken to her son about what to do in situations where he's confronted by police — and it was always to comply.

"'Whatever they ask you to do, do it. Don't say nothing,'" she advised him, adding, "So what's the difference in complying and you get killed anyway?"

Protesters gathered overnight near the scene of the shooting chanting "No Justice, No Peace" and "Prosecute the Police."

A noisy crowd also formed outside the governor's mansion in St. Paul, where police confirmed to KARE11 that Gov. Mark Dayton was in residence. Car horns honked constantly and protesters covered the railings in police tape.

The rain is not keeping people away. Minnesota Governor's mansion at 4:30am. #FalconHeightsShooting pic.twitter.com/useBMVJ5c9 — Tony Webster (@webster) July 7, 2016

Among the crowd was Minneapolis NAACP president Nekima Levy-Pounds, who called on Gov. Dayton to “wake up and make a statement” about the shooting. "This is completely unacceptable," she told the crowd. "Enough is enough!"

She earlier told reporters that Castile was "an upstanding citizen according to all the reports we’ve heard,” adding: "We just have a number of questions about how something like this could happen once again.”

Castile's shooting also sparked a massive outcry on social media, with many expressing dismay that two such incidents could happen in such a short time.

Hours after watching #AltonSterling, here comes another one in #FalconHeights. Each one seems to be more horrifying than the last one. — Jemele Hill (@jemelehill) July 7, 2016

Today I am not proud. Today I take action though I feel helpless. We can't stand for it! #blacklivesmatter #AltonSerling #PhilandoCastile — Connie Britton (@conniebritton) July 7, 2016