HOUSTON -- Police are now investigating the circumstances that led to the deaths of eight dogs in the back of an animal control officer's truck last week. Meanwhile, the city acknowledges that the air conditioner on the truck was not working when the animal control officer returned to the shelter.

The dogs died of heat stroke as the animal control officer stopped for lunch. Beverly Tucker said when she returned to her truck the air conditioning unit was nonfunctional and the animals were in distress.

Tucker insists that the A/C was working properly when she went inside the restaurant to eat 40 minutes earlier.

City officials said nothing like this has happened before.

“This is not something that has happened to us before, so I can't say it's standard procedure at all,” said Kathy Barton, of the Houston health department, which oversees BARC.

That's not true, insisted former BARC veterinarian Sam Levingston.

11 News: You have witnessed yourself, animals being brought in on trucks that had faulty air conditioning (that were) dead on arrival?

“Yes, I certainly have,” said Levingston.

After he was fired from BARC in 2000, Levingston sued the city under the state's whistleblower laws. He testified that, among other things, animals would sometimes arrive at the shelter dead because of faulty air conditioning in the trucks.

Levingston won the lawsuit and was awarded 1.2 million, but settled with the city for 875,000 to avoid an appeal.

Levingston said he thinks Tucker is being used as a scapegoat by BARC.

“They feel like they have done nothing wrong, and they like to fine someone they feel has done something wrong,” said Levingston.

For now, Tucker can keep her job, but said her supervisors already told her would likely be fired.

A vigil was held in front of Houston's city hall on Friday night in memorial to the dogs that died. The event was actually designed to bring attention to the lack of funding BARC receives each year.

About 50 people and three dogs participated in the vigil.