Presumably WaPo verified the claims made in this article. Frankly, I find it very easy to believe. It reminds me of the case of a man pulled over for a minor infraction (not wearing a seatbelt?) and the cop was
convinced the man had drugs. He searched the man, the car, and found nothing. Called a search dog. Claimed the dog found something - and wanted a cavity search. Dragged the man to a hospital to
force him to be cavity searched - the doctor refused. At the next hospital, the doctor agreed. They found nothing, of course. Then, the hospital proceeded to
bill the man they searched for the procedure. He's suing the hell out of the police department, but who knows what will happen.[1]
And then of course there was this woman, who had something similar happen.[2] And you know that they are not the only ones - they are just the ones who made a stink about it and got national news coverage.
More generally, prosecutors love leverage, the more the better (which is a big reason why they don't want to legalize pot). They leveraged Aaron Swartz, too.
I trust the Washington Post - and I further trust that if the WaPo made a mistake, the Manassas PD and DA would be making a big stink about it.
Who I don't trust are juries who, like you, still have an irrational belief in the government and the police - that they are infallible, impartial, and concerned only with serving justice and keeping us safe. The truth is that they are vicious, prejudiced bullies who have a tremendous amount of unchecked power and almost no accountability, operating within a complicated system that they have mastered against suspects who are often cowed in to pleading guilty just to avoid inordinate punishment for things they never did. It's a shit show.
[1] http://www.cnn.com/2013/11/06/justice/new-mexico-search-laws...
[2] http://www.elpasotimes.com/latestnews/ci_26100843/aclu-woman...