DENVER -- Denver police have determined that there was no criminal intent in the fatal mauling of a zookeeper by a jaguar in late February.

Denver zookeepers made heroic efforts to save Ashlee Pfaff, 27, after she was attacked by "Jorge," a 6-year-old jaguar, on Feb. 24.

Pfaff died from her injuries, despite rescue efforts that ended when the jaguar was shot and later euthanized. The autopsy report said she suffered a "blunt force/shearing injury" to her neck.

The Denver Police Department's report does not explain why a door was left open that allowed the jaguar to attack the woman. The report said a padlock was found on the ground near the animal's cage.

"We talked to multiple witnesses," said police department spokesman Sonny Jackson. "There was nothing criminal, where anybody did anything to cause her death."

The police report includes statements from 20 employees. One of them told police, "The jaguar leaped at the keeper and grabbed her by the head, and she began screaming."

Other zookeepers came to her aid. One worker sprayed the animal with a fire extinguisher. Another told police he retrieved a 12-guage shotgun, went to the feline building, and saw the jaguar standing on top of the victim.

Derek Cassaboon told police, "When the jaguar moved to the north it picked up a piece of meat from the ground."

The report goes on to say, "the jaguar dropped the meat and then took a few steps back towards Cassaboon, who then shot the jaguar."

A zoo visitor witnessed the attack and alerted zoo employees, the report stated.

Jackson said that no charges would be filed in the case, but other investigations are still ongoing, including an internal investigation by the Denver Zoo.

Zoo officials released a statement early Wednesday. It states in part: "Denver Zoo is still actively investigating the accident and continues to fully cooperate with OSHA, USDA and other agencies. While Denver Zoo's internal investigation continues, it would be premature for us to share our findings."

The zoo statement indicates that Pfaff underwent regular safety training, that she shadowed veteran keepers (on the job), and attended mandatory safety meetings.