Two Denton animal shelter workers have been suspended for their roles in the accidental killing of a dog last month.

Police Chief Roy Minter, who called for the suspensions, also detailed the policy changes he promised in the aftermath of the death, which received widespread media coverage.

"We had good policies and procedures in place," said Chief Minter, whose department oversees the city-run shelter. "But this has given us the opportunity to say that we can enhance those policies and procedures."

The May 15 euthanizing wasn't the first such mistake at the facility, a Denton Record-Chronicle analysis found.

In 2006, a worker accidentally euthanized an Australian shepherd after an employee "failed to follow the established procedures," according to internal records. The dog's owner, Amy Kendall, didn't sue after being assured that policies were changed to prevent another accidental killing, she said.

"I was trying to do the right thing, not do a frivolous lawsuit or anything like that, but now I see the error of my ways," Ms. Kendall said. "If I would've made it a bigger deal, maybe it wouldn't have happened again."

Police officials called the incidents aberrations for a normally well-run shelter. The cases were different enough that changes made in 2006 didn't apply to the recent death, they said.

"Yeah, this was an ugly situation," said Chief Minter, who became police chief last August. "It should not have happened. But this is in no way, shape, form or fashion indicative of what those folks do on a daily basis over there."

Shawn Snider and Beth Bayless-Snider, whose dog the city euthanized on May 15, did not return messages seeking comment.

The city picked up the Sniders' 3-year-old black Labrador mix on May 8 after it escaped from their yard. When they arrived to retrieve it May 15, they learned that a worker had killed it that morning. The worker apparently didn't notice an entry on the dog's records saying the Sniders arranged to pick it up May 16, police officials have said.

The city suspended two animal control officers without pay. Debbie Lhotka received a two-day suspension for the euthanasia error, while Robert Sprabeary was suspended for three days for "poor customer service" in dealing with the Sniders, said Laura Hornung of the city's human resources department.

Mr. Sprabeary declined to comment through police spokesman Jim Bryan. Ms. Lhotka could not be reached for comment.

Shawn Snider called for the firing of at least one of the workers. He and his wife are also asking the city for $206,000 for the loss of the dog and future breeding opportunities, along with "emotional pain and stress."

When media outlets picked up the Sniders' story, friends started calling and e-mailing Ms. Kendall to see if she'd heard the news.

For her, the case was all too familiar.

On Feb. 27, 2006, the shelter accidentally euthanized her 5-year-old Australian shepherd, Rocco, after a worker mistook it for another dog. Animal control officers had seized and quarantined Ms. Kendall's dog a day earlier after it reportedly bit a neighbor who reached over her fence to pet it. Quarantined animals are supposed to be held 10 days for rabies testing.

The worker responsible for the error, Michael Green, served an unpaid three-day suspension, said Officer Bryan, the police spokesman. Mr. Green later quit for "personal reasons," Officer Bryan said, and he could not be reached for comment.

Ms. Kendall didn't sue after the city paid her $700 for a new dog and promised to make changes at the shelter.

Mr. Green referred to the new policies in an April 3, 2007, apology letter to Ms. Kendall.

Ms. Kendall said she never received the apology letter. But in earlier correspondence, police officials promised to apply new safeguards, she said.

Officer Bryan said safeguards added in 2006 concerned the quarantine process, which did not apply in last month's case.

In response to the new death, the police chief ordered more safeguards to make sure animals aren't mistakenly picked for euthanasia.

Chief Minter also is increasing the number of surprise inspections at the shelter and moving up a planned internal review of its operations, among other changes.