DENTON, Texas—A couple whose dog was mistakenly euthanized want the city to pay $206,000 for the loss, future breeding opportunities and emotional pain.

Shawn Snider and Beth Bayless-Snider say they arrived to pick up their 3-year-old black Labrador mix on May 15 and found out a worker had killed it that morning.

“I’m not going to just let them get away with an apology,” he said. “They can’t bring my dog back, so the only thing they can do is give me money.”

The worker apparently didn’t notice an entry on the dog’s records indicating the owners would pick it up May 16, said Lt. Lenn Carter of the Denton Police Department, which oversees the shelter. The Sniders arrived to pick up the dog a day earlier than expected.

An investigation is under way and the shelter worker could face discipline, Carter said. He declined to name the worker.

“It was definitely a mistake on our part,” he said. “It’s a really unfortunate incident, and we’re going to take steps (so) that it doesn’t happen again.”

The Sniders filed a liability claim with the city’s risk management department. City spokesman John Cabrales said officials could not comment on a pending claim.

The couple also haven’t ruled out a lawsuit, Snider said.