Taking possession after foreclosure, looks vacant but not sure

[Ivan Vargas]

I got my CT and went by the property, ring the bell and knock on the door no answer. Went back at night and no lights on or AC running. Place looks abandoned like a typical foreclosure. However I spoke to the property manager at the HOA and he says the owner was living there not a tenant but cannot confirm whether he still lives there or not.

My questions are, since there's no one home to offer CFK: 

Can I just go ahead and enter the property and change the locks without Writ of Possession? 

What would happen if I drill the locks and go inside only to find personal belongings and evidence that the owner still lives there and is maybe at work or something? Assuming this is illegal, what would be the consequences even if I thought it was vacant?

Should I first post a little note on the door with my number and wait a day or two? Or should I just go ahead and get the writ of possession even if when I arrive it isn't necessary?

I know he is well aware of the foreclosure because he's been fighting it for years and 3 times filed an emergency motion just days before the sale day forcing them to reschedule, this time he filed the morning of the sale, the judge denied the motion and the sale happened. 10 day redemption period has passed and CT was issued.