A confidante of indicted state Sen. Vincent Fumo will admit in court that he, Fumo and others used more than $200,000 in state Senate funds on campaign work, documents show.

Federal prosecutors preparing for the powerful lawmaker’s fall corruption trial filed a plea agreement Thursday signed by campaign consultant Howard Cain.

Cain, 60, of Wayne, also admits he failed to pay $411,000 in taxes on $1.6 million in income from 1997 to 2006 — and that he filed no tax returns from 1991 through 2006, the documents show.

The Senate Appropriations Committee paid Cain about $80,000 a year from 2000 to 2006, when Fumo served as ranking Democrat. Those contracts provided roughly half of Cain’s annual income.

Cain also served as Fumo’s campaign consultant during at least some of that time.