This particular case happens to be in Florida.NOTE: do not be like this Landlord and confront the squatters unless you are prepared to defend yourself.

When I confronted the Section 8 caseworker he told me there was nothing he could do about it.

The sheriff will post a notice of their own on the entrances to the premises, then will enter the unit to make sure it is clear or to confront the tenant, and then once the tenant is out, they will stand by as you change the locks and empty out the dwelling.This is not legal advice.

No need to be confrontational, just politely state the temperature will be set at X, if you prefer it warmer,  it is permitted to use portable heaters. 

Being a landlord means being confrontational sometimes .

I will let him know that there is nothing I can do and he needs to contact the police department (which he now does whenever a confrontation happens).

I do not know the landlord's angle for reporting a higher deposit.If you suspect fraud, don't confront your landlord, but rather report it to the county housing authority.

@Ian Walsh  No worries my friend promise no confrontation.

My gut tells me is was an agent that was previewing the property, but, of course, you never want to confront on something like that

Owning a management company we have to confront this issue pretty frequently.