An article I read about this yesterday states that Chapman is running in the primary against Parrish because Parrish supported last year's tax increase.
There's about a half a dozen RINO's like Parrish in the General Assembly who have primary challengers this year specifically because they voted for the tax increase.
In the 33rd district, the RINO incumbent (May), who in the past has not only supported higher taxes but also voted against bills for parental notification before a minor child has an abortion, has also resorted to using dirty tricks to try to have his opponent's name removed from the ballot.
http://www.timescommunity.com/site/tab1.cfm?newsid=14464163&BRD=2553&PAG=461&dept_id=506040&rfi=6
You are correct. Chapman is challenging the incumbent Parrish in this race because Parrish supported Governor Doofus's tax increase last year. The conservative base are supporting Chapman who is fervently anti-tax, pro-life and helped defeat a gambling initiative in the City of Manassas last year. That said, Parrish has generally been pretty conservative, even on tax issues over the years, but he squished out last year. It sounds as if his campaign staff are the ones who turned the evidence over to the Commonwealth's Attorney (who happens to be a Dem, but is the only one to get the death penalty for the D.C. area sniper and botched the Loreena Bobbitt case a decade or so ago.)