I've had the exact same issue with the petco about 45mins from here. I have a friend who lives in the same town that the petco is located and he actually finds live reptiles tied up in mesh bags in their dumpster out back. The first time he found 2 juvenile iguanas tied up in a mesh bag in the middle of summer on top of all the other trash. He went in to tell the manager and they didn't care at all. He's found tortoises, bearded dragons, veiled and Jackson's chameleons, baby monitors, corn snakes & ball pythons since then. Some alive some had passed. Now he goes everyday after he gets off work and right after they close to check.
Petco just doesn't care.
I would be very careful on this story. That guy is posted all over the boi on fauna for falsely placing iguanas there and such. I will not go into detail as this isn't a boi nor will it ever be but after researching the heck out of that story I feel that guy was lying about the two live iguanas for multiple factual reasons.
Also it is against the law to dumpster dive as he was and the petco stated they were locking the dumpster from on because there was great suspicion he is placing the animals in there (which I believe he is). As who would actually film themselves dumpster diving?