Neighbor's Wall is leaning Towards Our Property

[James Phan]

Hi Everyone,

Looking for advice on a situation I have with my Neighbor's leaning wall.

There's a 50ft retaining wall between my house and neighbor's house and that retaining wall belongs to my neighbor. My neighbor's property sits higher than us.

The retaining wall is beginning to lean to my house around 3-5 inches. 

Were installing a sidewalk next to it, and my contractor said the retaining wall is doesn't have strong foundation, and there's water pressure from our neighbors ground that push into that wall ( watering plan, raining systems going directly to the retaining wall).

We see signs of water from the neighbor into retaining wall and going to our side. The contractor said the retaining wall can potentially fall into our house and crack all concrete, worst it could hurt someone. Our contractor suggest to have attorney involve on this case before starting any work. I asked my friends who are lawyers, they all suggested to call home insurance ( Allstate) and home insurance will hire an attorney to review this case. 

Also, my neighbor's house has renters living there. Landlord is not present.

I'm looking for more feedback on ways I can deal with this?