Should I Call or knock?

[Carlos Caloca]

Hey BP! Quick question. (Let me preface by saying I'm still looking for my first deal) So I was driving around and found this boarded up house talked to the neighbor and she said house has been abandoned for at least a year. I then went to the county assessors office and looked up the address and found the current owner and address I also looked online for the owner and found a phone number my question is should I call or go knocking on their front door? Thanks for any and all advice Oh yes I forgot to mention house is 8,000 in backed taxes