Chilling new footage shows the crazed gunman who murdered a Canadian tourist and wounded 13 others at an ancient Mexican pyramid strolling by with a backpack full of ammunition — before setting up his gun and opening fire as terrified tourists scatter.

“Get down! Get down!” a frightened onlooker can be heard shouting as gunshots ring out,  prompting people at the Teotihuacan ruins to run for cover.

Julio César Jasso Ramírez —  a 27-year-old Mexican national who was obsessed with Hilter — is seen wearing a mask as he walks into the foreground of the frame before picking his lethal perch on the Pirámide de la Luna.

Tourists then duck for safety in a horrifying moment of chaos as he sprays bystanders with bullets.

“All we could hear is shot after shot … and we just didn’t know where these shots were going to. We didn’t know if they were coming towards us,” said Yazmin Salcedo, of Texas, whose husband, Joel Torres, filmed the footage while on a vacation. “That’s why we just kept running and running.”

Torres and Salcedo, were on a trip with their son and daughter-in-law, when Torres caught the attack on camera while filming the pyramid on a 360-degree camera, the couple told NBC Dallas-Forth Worth.

“He walked in front of us, sat himself down … It wasn’t even a minute. It was less than that when the first shot happened,” Torres said.

“Thank God … there were not more people killed because he really had the opportunity to shoot everybody that he could out there,” he said.

Ramírez shot dead a Canadian woman, while six Americans, three Colombians, one Russian, two Brazilians and one Canadian were taken to the hospital Monday.

He climbed midway up the pyramid— a nearly 2,000-year-old structure that was once used for ritual human sacrifice —  and opened fire with a 1968 Smith & Wesson gun before turning the gun on himself, Mexican authorities said.

Authorities later found him armed with 58 rounds of unused ammunition.