Former Pennsylvania Democratic House Whip Mike Veon, left, arrives in handcuffs for his arraignment Friday in Harrisburg. Veon and 11 others are accused of a criminal scheme to have state taxpayers fuel political activities and underwrite personal perks.

HARRISBURG — Armed state agents brought current and former Democratic state lawmakers and legislative aides to their arraignments in handcuffs Friday to face charges that they used taxpayer dollars to fuel political activities and underwrite personal perks.

All 12 defendants went free on bail or their own recognizance.

Attorney General Tom Corbett, a Republican, announced the charges Thursday after a yearlong grand jury investigation that is ongoing. The charges include various counts of theft, conflict of interest and conspiracy and amount to the state's largest political corruption case in recent memory. Preliminary hearings are scheduled for Thursday.

Corbett said his office also is investigating Republicans in a probe launched by a January 2007 report in The Patriot-News of Harrisburg on the secret bonuses that legislative leaders had doled out to aides.

In all, Republicans and Democrats in the House and Senate awarded nearly $4 million in bonuses to their employees in 2005 and 2006. More than half the total was distributed by the House Democrats.

Michael R. Veon, who was the second-ranking Democrat in the House before losing re-election in November 2006, allegedly helped mastermind a vast operation to enlist taxpayer-paid legislative aides as workers on Democratic political campaigns while on state time, awarding generous bonuses from the state treasury as incentives.

He also allegedly arranged taxpayer-paid dinners for himself and fellow Democratic lawmakers and aides after basketball games, amassing $22,000 in expenses over four years. He reimbursed two employees nearly $1,500 in public money to take his and his wife's motorcycles to a 2004 rally in Sturgis, S.D., so the bikes would be there when they flew in, the grand jury found.

One defendant, Democratic House lawyer Jeff Foreman, turned himself in Thursday. Two others, husband and wife Scott and Jennifer Brubaker, were allowed to arrive without handcuffs.

The rest turned themselves in at the Lower Paxton Township police department to be photographed and fingerprinted before the arraignment.