$0 Title Recorded? Why?

[Bianca M.]

Interested in trying to understand this -- wondering if anyone can help:

Someone that I don't know personally is flipping houses.  I like to use the towns assessors website to compare what they purchased the property for versus what they are trying to list it for, as I am personally interested in flipping houses/multifamilies. 

I noticed that one of the houses the flipper had for sale -- sold -- but what's odd is that the original $$$ value recorded at the tax assessors office went from $80K to $0 prior to it becoming listed,  What would cause the flipper to show a $0 value, when originally they had purchased the property for $80K.  And, why would a flipper do this (and how)?

Looking for your thoughts...thanks in advance.