New video appears to show George Floyd struggling in the backseat of a police cruiser with three Minneapolis officers

• Activist Shaun King shared a video on Instagram that provided yet another look into the killing of George Floyd while in police custody on Monday.
• The footage picks up after Floyd, 46, is in the backseat of a Minneapolis Police Department cruiser.
• A struggle appeared to be underway, with three officers leaning into the car and one watching while standing beside the vehicle.
• It would've been after this struggle that Floyd wound up under the knees of three police officers, gasping, "Please, I can't breathe."

A video of George Floyd's final moments, gasping for breath with a Minneapolis police officer's knee on his neck, has gripped the nation and become a flashpoint of outrage and racial tension that has morphed into protests, riots, and civil disobedience.

However, on Saturday, activist Shaun King shared more footage on Instagram that shows, from a different vantage point, the minutes leading up to Floyd's death.

Floyd was arrested Monday outside Cup Foods after police arrived on the scene to investigate reports of forgery. The 46-year-old man was sitting in a parked car with a man and a woman. They were approached by officers, led out of the car, and Floyd was then handcuffed and led across the street to a police cruiser, out of the frame of the security camera from which NBC News obtained surveillance footage.

King's video appears to pick up where the other footage left off. By this point, Floyd is in the backseat of a squad car and a scuffle seems to be underway.

Doors on both sides of the car are open, and three officers can be seen leaning into the car. One's feet are visible beneath the right backseat door that shakes, and then he runs around to the other side where two other policemen's heads are visible. A fourth police officer keeps watch, with his hands in his pockets.

In the days since Floyd's death, another video has also surfaced showing three officers pinning him to the ground while he begs, "Please, please let me stand. Please, I can't breathe."

All four policemen have been fired from the Minneapolis Police Department, and the arresting officer, Derek Chauvin, faces third-degree murder and manslaughter charges.

On Sunday, White House adviser Robert O'Brien talked to ABC News anchor George Stephanopoulos about the conduct of officers who watched Floyd die.

"It's an absolute outrage," he said. "I can't imagine that they won't be charged. To have stood by and allowed that to happen … it shows a lack of humanity."

• Read more:
• NY police commissioner says he's 'extremely proud' of department as videos surface showing officers using excessive force and plowing cars into protesters
• Across America, police violently arrested and shot less-lethal rounds at journalists covering George Floyd and Black Lives Matter protests
• The National Guard says its activated 5,000 troops to respond to unrest in 15 states and DC with thousands more ready to go
• Twitter changed its profile to honor Black Lives Matter amid George Floyd protests
• The Minneapolis police officer who knelt on George Floyd's neck has been arrested. Experts say prosecutors have a long road ahead.
• Derek Chauvin had 16 complaints made against him that were closed with 'no discipline.' A former member of the police review board says that's proof of a broken system.
• People keep sharing the video of George Floyd. Some activists and mental health professionals are calling it 'pain porn' and begging them to stop.
• Most Minnesota law enforcement agencies ban the neck-pinning maneuver used against George Floyd – but it's still allowed in Minneapolis