Holding suspected illegal immigrants in jail in Prince William County (web|news) has cost nearly $800,000 more than expected in the previous fiscal year, officials said.

The so-called 287(g) program permits local law enforcers to assist Immigration and Customs enforcement in processing illegal immigrants. But the program has used far more jail resources than expected, according to jail superintendent Col. Peter A. Meletis.

The increased cost was first reported by The Washington Examiner.

"Resources needed to support the program were estimated or unfunded due to the uncertainty of the size, impact or cost of the program," Meletis said Tuesday. He added that projected revenue was "equally uncertain."

When the county got involved last year, officials weren't sure how long the county would have to house suspects.

Federal immigration officials were taking weeks, not the 72 hours agreed upon, to pick up suspected illegal immigrants. This led to crowding at the jail.

The cost to house detainees surpassed the budget by $413,000. Other higher-than-anticipated costs included almost $130,000 in unbudgeted overtime and $179,000 in medical and drug costs.

The county has been reimbursed by ICE for all the additional expenses. But the Board of County Supervisors voted at its weekly meeting Tuesday to apply the roughly $800,000 to the shortfall in the 2008 budget, which ended June 30.

Prince William spent the money and expected to be repaid, County Executive Craig S. Gerhart said.

The board nearly emptied its contingency reserves earlier this year, when it transferred nearly $800,000 to pay for the startup costs of the crackdown on illegal immigrants.

"We knew this was going to be expensive when we did it," Supervisor Maureen S. Caddigan said.

The Adult Detention Center budget was $32.9 million in the last fiscal year. Its adopted budget this year is $39.7 million, 20 percent higher. The cost to house and feed an inmate was $97.52 a day, an increase of $2.17 from 2007. The increase resulted from added supplies, increased transportation and other costs related to the crackdown.

Prince William's 287(g) agreement has been in effect since July 2007.