The rodents are enjoying marijuana at the Houston Police Department that has been sitting in evidence for years.

To illustrate the problem, Houston police Chief J. Noe Diaz pointed to one piece of cocaine evidence from 1996 that was still in the lockup. The individual tied to the drugs pleaded guilty, was sentenced to 20 years in prison and has since been released, he said.

"Drug-addicted rats" are eating narcotics seized and stored by Houston police, prompting a change in how long the department is required to store the evidence, officials said.