A Denver police officer assigned to the mounted patrol unit was penalized one vacation day after documents show he left his horse tied up in a stall for 16 hours without food or water.

Officer Joseph Teeter was docked one eight-hour vacation day for the violation. The horse eventually had to be put down.

A Denver Department of Public Safety Disciplinary letter, served on Dec. 20., says when Teeter finished his mounted patrol shift on Sept. 26, 2016, he returned to the Denver Police Mounted Patrol Barn and unloaded his horse into a stall.

Teeter tied his horse, named MC Hammer, with a rope, which left about two to three feet of slack, and removed the saddle.

The document continues to say that Teeter "became distracted doing paperwork and forgot he had left the horse tied in the stall."

At 6:15 the next morning, MC Hammer was discovered still tied to the eyebolt in the stall.

During these 16 hours, the horse had no access to food or water, the letter states. Despite getting fed and watered the next morning, horse had to be euthanized the next day after it developed colic.

The letter states, "The medical experts who evaluated the horse were unable to conclude that the horse's condition was caused by being left in the stall without food or water for approximately sixteen hours."

"Abandonment and even just negligently failing to provide sustenance is a crime in Colorado," Justin Marceau with the Animal Legal Defense Fund said. He's also a law professor at the University of Denver.

Marceau says leaving an animal without food and water can be considered abandonment. The law doesn't say for how long the animals has to be left alone before it’s breaking the law.

"It might be difficult in some cases to prove forensically that something caused the death of an animal," Marceau said.

Teeter was disciplined for a violation of the Denver Police Department's Written Command: Rough or Careless Handling of City and Department Property. That particular violation can carry various disciplinary actions, including up to three "fined" days.

Teeter received one "fined" day, or eight hours of docked vacation time for 2017.

The letter states Teeter's service record and commendations as mitigating factors, but stated the officer's forgetfulness put the horse in "cruel" conditions. It also said Teeter demonstrated real remorse for his actions.

"I know he was devastated at the time of the incident," Christine Downs said, Denver Police spokeswoman. "I'm sure he still carries that with him."

When the case was passed along to the district attorney's office, they didn't press charges.

Teeter is still assigned to the Mounted Patrol.