Accidental landlord. Partial rent payments and undocumented

[Michael Conte]

Hoping to get some advice to help a friend

She inherited a rental property from her late parents. As of august the tenants are behind atleast 5k in rent. Tenants have been occupying the property for over 10 years. I walked the property today and its not in terrible condition but the tenants are definitely subletting as there are far more beds than people who are supposed to be living there. she believes the tenants are undocumented. property is in nj. 

I would love to help her get them out and rehab the property as they are currently leased at $1500 of which they dont always pay and the market for her house is $2800. Since she owns the property out right, that $2800 would be a cash cow and nice back up retirement plan. 

I tried to gather as much info as i could but if any further details are needed for a potential resolution i can get them from her. 

any and all input is appreciated!