CALGARY, Canada (WTNH)– A river otter was killed at a Canadian zoo by an unauthorized pair of pants, zoo officials said Wednesday.

A 12-year-old American river otter named Logan, drowned at the Calgary Zoo after he became entangled in a pair of pants that had been given to the otters as an enrichment item, according to the zoo’s curator.

The zoo posted about the death on their Facebook page, stating that the investigation identified that zoo protocols were broken by two staff members, who will be disciplined.

The zoo’s curator said in the statement that “this error is unacceptable. Our animal care protocols are among the most stringent in the industry and must be followed. We will be reinforcing our protocols with every member of our Animal Care staff to prevent an incident like this from ever happening again.”

However, according to BBC, this isn’t the first incident with animal deaths at that zoo. In 2013, a penguin died after swallowing a foot-long stick and a spider monkey died of frostbite after being left outside. In 2009, there was also an incident of a gorilla wielding a knife that a zoo keeper accidentally left in its enclosure.

The discipline the zoo staff will be given for the otter death is unknown.