San Diego mosque killer Caleb Vasquez urged his accomplice to shoot him in the head in a twisted exchange captured on a livestream broadcast after the pair murdered three people.

Vasquez, 18, is seen in the passenger seat of the white BMW he and 17-year-old Cain Clark used to flee the Islamic Center of San Diego, in footage captured by a camera the pair placed on the car’s dashcam while the vehicle was stopped.

Vasquez grabs the barrel of Clark’s rifle and brings it to his own forehead at multiple points in the livestream clip. The video, circulating on social media, did not have audio.

Finally, the camera turns to include only Clark — sitting in the driver’s seat — who uses his pistol to shoot Vasquez in the head twice and then turn the gun on himself.

The FBI is currently investigating the livestream video, law enforcement sources told The Post.

The livestream also showed the teen terrorists descend on the Islamic Center, opening fire.

During the attack, both men were decked out in Nazi gear, including a Black Sun symbol, which is associated with Nazi Germany. Nazi SS commander Heinrich Himmler had the symbol inlaid into the floor of the Wewelsburg castle.

The two also had hate speech written on their weapons, including the phrase “Race War Now.” The two also left behind a shocking, hate-fulled manifesto before the terrorist attack — which praised Adolf Hitler and a slew of mass murderers.

Three men, including the center’s security guard, Amin Abdullah, were killed in the attack.

Abdullah’s daughter, Hawaa Abdullah, honored her dad at a press conference Tuesday.