The resident showed a photo of the animal to police, who suspected the animal was more likely to be a lizard than an alligator.
David Heithoff, owner of the Critter Control franchise in College Station, was then contacted by the resident and responded to the home, where he caught a quick glimpse of the animal before it fled into foliage.
"I've caught a lot of alligators -- not around here, but a lot of alligators -- and I've seen nothing like that," Heithoff told The Eagle newspaper.
Heithoff said a colleague identified the animal in the photos as a tegu monitor lizard, a species that is not native to North America.
The pest control expert said he believes the tegu lizard was a former pet that either escaped or was abandoned by its owner. He said it appeared to have been living outdoors for several months.
Heithoff said the lizard was captured in a lethal trap. He said he would have had to euthanize the animal if it was captured alive due to the difficulty in finding a facility to take in the lizard.
The lizard, which measured a total 3 feet, 2 inches long, was a female full of eggs, Heithoff said.