HOUSTON -- Eight dogs died last week after they were left in the back of an animal control officer's truck without air conditioning. An investigation is ongoing to determine if the truck's air conditioning unit failed or if the animal control officer forgot to turn it on.

Temperatures on Aug. 26, the day when the dogs died, peaked at 95 degrees. When the animal control officer stopped for a lunch break, she said the air conditioning unit was working properly.

When she returned to the truck about 40 minutes later, she found the animals in distress and the air conditioner was not working. Six of the dogs died in the truck, while two others were euthanized at the animal shelter.

Houston Mayor Bill White called the incident “unacceptable,” and said, “I don't think people should be taking lunch breaks with a bunch of animals in their truck.”

The dogs' deaths are a shock, especially for those who fight against the crisis of pet overpopulation in the nation's fourth largest city.

Earlier this summer, when 11 News rode along with another officer from Houston's Bureau of Animal Regulation and Care, he was kind, compassionate and above all, professional.

BARC officials said it is common practice for animal control officers to take lunch breaks with animals in the truck, because the air conditioning unit is there to protect them.

Whether it's a question of equipment breaking down or the quality of some of the people being hired, critics said it boils down to one thing – a lack of funding.

The cities of Austin, El Paso, San Antonio and Dallas spend more money than Houston. Dallas spends four times as much as the Bayou City.

While the City of Houston is spending more, the mayor said pet owners need to bear the responsibility of keeping strays off the street.

“It's not just spending, it's private owners taking responsibility for their animals,” said White, who also stressed that more people should be willing to adopt a stray.