1. He's a cockroach (possibly a cucaracha)
2. Alleyways are almost ALWAYS non-private property and are NOT the responsibility of the adjacent property owners/dwellers. In other words, if the public can drive on it, it's public. The biggest giveaway is the utility pole he's stacking the bags near....that pole is in a utility easement in the ROW (Right-O-Way) which is public, not private, property. ROW's exist on both sides of any and all public roads and alleyways for maintenance reasons and for reasons just such as this issue.
Your local county's GIS / property tax maps usually clearly define the properties, including the ROW. I'd find it, print it out and have that with you when you complain / file report with your images.
BOTTOM LINE: IMO, it is NOT the responsibility of any adjacent property owner / dweller to clean that up...it is the responsibility of the city / town if within its borders or the county's if not.
Some time ago Phoenix changed the designation, and ownership, of the alleyways. They (the City) retain right-of-way for public utilities, but ceded ownership to adjacent property owners up to the mid-point of the alleyways. I wasn't living here then and I never asked my folks about the specifics, but my guess is this was a cost-saving move for the city. They decided to push off responsibility for alley maintenance and clean-up to the residents. They also enacted new ordinances making it illegal to use the alley as a thoroughfare and stating that only residents are to have alley access. This makes it technically illegal for people who are not residents to transit the alleys, but as you can see in my captures, it's a law that is frequently violated. The City periodically surveys the alleys and writes tickets for residents who have trash or overgrown vegetation extending into the alleys. The only time the City will not take action against a resident, is if the illegal dumping is reported promptly. Criminals often use the alleys for ingress/egress to/from their victims. The alleys are largely unlit unless homeowners have installed lighting, and it is rare for residents to surveil their alleyways. As my home is on a corner and near to a deteriorating mall, I see so much activity it necessitated installation of security cameras. Even with them, I've had cretins jump the fence and get into my carport and yard looking for something/anything to steal. The cameras alerted me and they were shooed away, but it is a constant battle.
Edit to Add: It does provide plenty of opportunity to provide interesting camera captures though.