That was dumped out of a truck by someone.

Having their name on the box or a piece of mail isn't proof they dumped it. Back in the day, when we had LEOs (Litter Enforcement Officers) who investigated illegal dumping, they often found the people were dead or had moved. The live ones may have hired a private hauler to take it to the dump and the hauler dumped it on the street. People rarely ask for a receipt from the dump.

I spoke to the manager of a business whose boxes were dumped in front of a community center. The boxes had contained merchandise the business sold. Whoever bought the merchandise (likely someone doing a renovation) dumped the boxes.

One seeclickfix reporter repeatedly saw the driver of a U-Haul dump renovation debris in his neighborhood. He found out who rented the truck. It was a local Oakland woman. I don't know if the city pursued it or not.

A lot of tough talk with little actual action.

http://oaklandlocal.com/2013/09/oakland-gets-tough-on-illegal-dumping/

This is what the city attorney wants from us if we witness illegal dumping:

For dumping in progress call OPD non-emergency line (I know, I know):

(510) 777-3333

otherwise:

Public Works Agency Call Center (510) 615-5566

Tips for submitting evidence:

Photos of vehicle license plates are ideal. If a photo is not available, write down the license plate number.
Include time, date and location.
Include your contact info – the City must contact you to verify evidence.
More information is always better – photos of company names or logos on vehicles involved in dumping may be helpful.
Avoid confrontation when documenting illegal dumping incidents.