By Jason Allen, CBS 11 News

ARLINGTON (CBSDFW.COM) – Animal rescue groups are accusing Arlington animal services of euthanizing dogs and cats that people are trying to adopt.

The city however said it’s proud of its department and constantly working to improve it, while admitting to dropping the ball in the case of one dog.

A half dozen different rescue volunteers told CBS 11 it is common to tag animals for rescue, only to go to pick them up and find that they’re gone.

Volunteer Katie Blackshear said she was in line at the shelter to pick up a group of kittens last week, when she learned they had been euthanized.

“There’s no telling how many families have lost their cats, just because of laziness,” Blackshear said Friday.

Volunteers said the city regularly sends out a list with descriptions of the animals that are scheduled to be put down. Volunteers have until 2 p.m. to tag an animal for rescue.

Several though said they get no confirmation if their emails are received, and phone calls regularly go unanswered.

They are also concerned animals are being labeled as wild, untreatable or unhealthy which increases their chances of being euthanized.

Blackshear demanded to take home two cats labeled that way the same day her kittens were put down.

She said the cats were fine after $12 worth of veterinary treatments. “I’m not going to go spin my wheels down there and have these kind of things happen to me. I can’t take it,” Blackshear said. “It’s just too much.”

The shelter has taken in 5, 123 dogs and cats since October, an increase of 11-percent.

Partly because of that, the live release rate at the shelter has dropped to 47-per cent, nine points lower than last year.

But the number of animals adopted out has also increased. Rescue groups have saved 786 dogs and cats this year.

In a detailed response to a long list of complaints from volunteers, the city explained why some cats are listed as wild.

“Cats are reevaluated each day to determine temperament changes. If a cat proves eligible for adoption during the 3 or 7 day holding period, it is transferred directly to adoption,” the explanation read.

The city said a black lab that was put down after two people expressed interest before the deadline, had an upper respiratory infection that made it ineligible to adopt.

A city spokesman did admit that staff “dropped the ball” in the case of a husky with two-inch nails and matted fur that for some reason were not treated.

But in a letter to animal groups a city spokesman wrote, “We are progressive in our approach and remain committed to ongoing operation improvements.”

In the same letter the city said it is adding a supervisory position to community outreach.

It is also providing direct contact information for rescue groups and a dedicated placement hotline to get information easier.  For more information, click here.