Neighbor disputes property line - leaves junk on our lot

[Lois S.]

We have a SFH on a cul-de-sac, so the lots at the end aren't straight rectangles. The neighbor is claiming that a small section of our lot is his. (It's not, as clearly shown even on Google maps) Our mutual backyard fence -- if extended in a straight line to the front of the lot-- clearly defines the lots.

The neighbor was asked by our tenant to remove some things from a section of our lot that adjoins the neighbor's.  Neighbor says it's his lot. (Tenant is moving out soon)

(Items are several bicycles, cold storage chests, junk) 

I've never met the neighbor, but he seems to be a hoarder:  so many cars in the driveway that may or may not run, that sometimes end up partially parked over the sidewalk.  

I was preparing a friendly letter asking for him to remove his things, along with the schematic of our lot lines from the County maps website included.  My understanding is that his English is not great, so I'm reluctant to go try to talk to him. And also I don't want a confrontational situation.

City code enforcement says they don't handle this type of case.

If the letter is ignored, what are next steps?  Attorney? 

Thanks for any useful input.