You could hire an attorney that specializes in such things....
Or,if you are a stubborn Smart "A"
YOU COULD TRY "MY WAY"
TAX roles are PUBLIC INFORMATION they must be made available to anyone who applies for the information...THIS IS WHAT YA' GOTTA' DO: FIND THE NAMES ADDRESSES AND ASSESSMENT of each and every ELECTED OFFICIAL, POLICE CHIEF, JUDGE AND THEIR CHILDREN. Should you find discrepancies and disproportionate tax and valuation figures, put it together in a package to your STATE ATTORNEY GENERAL
Naturally, because these are public officials you could also CC your Local Federal Prosecutor...They eat this stuff up, love 'em!
It takes courage, BUT I WILL BET THAT YOUR "PUBLIC SERVANTS" ARE FAVORED WITH LOWER TAXES....Then YOU HOLD THE HIGH CARDS...
You might become popular, feared, hated, or worse...but what an adventure!!!
PS: Be MOST explicit when you get the Ms. Tax Assessors figures...Tell her your helping out a friend, but you can't divulge who it is or, naturally he could do it himself!!! [that'll keep her awake at night