Animal rights groups and other activists demonstrated outside the Lethbridge Police Headquarters on Sunday to rally against the actions of one of the city’s officers last week.

About 100 men, women and children set themselves up outside the LPS headquarters on Sunday afternoon, all chanting and waving signs to express their disappointment with the force.

"Within the first three seconds of the video, you could hear the deer crying, and that's all I could handle, with tears coming down my face," said Lois White, one of the protesters.

On January 5, a police officer was caught on camera allegedly using his truck to euthanize a deer that had been seriously injured after it had been struck by a vehicle on Scenic Drive South.

In the video that was shared on social media, the officer was seen running over the animal several times before it finally died.

Two days later, the Lethbridge Police Service was made aware of the incident and told the media on January 8 that the Alberta Serious Incident Response Team has taken over the investigation.

Since then, ASIRT says it has been made aware of a number of death threats made against the unidentified officer, who has remained active pending the outcome of the investigation.

Many people who attended Sunday's demonstration said the officer should have called Fish and Wildlife officers to deal with the animal and the decision that was made was the wrong one.

"[They should] done something else instead up just using such a cruel way to put the animal down," said Kathy Braun.

An online petition calling for the officer to resign has surpassed 60,000 signatures.

Organizers of the protest say the officer should be suspended pending the outcome of the investigation and be order to undergo a psychological assessment. They also want to see animal cruelty charges laid against the officer.

ASIRT is continuing to investigate the incident.