CHICAGO — WGN News and The Better Government Association have learned that the U.S. Attorney has opened a criminal investigation into the expenses of powerful Cook County Commissioner William Beavers.

A grand jury is investigating longtime politician Beavers and his use of a Cook County expense account.

The former Chicago Alderman who appointed his daughter to his city council seat after he ran for County Commissioner.

The Cook County Board was issued this subpoena about commissioner beavers’ use of his so-called contingency expenses.

The grand jury wants his expense reports from 2008 and 2009. At that time, every county board member got contingency expenses of $1,200 a month for business purposes, or more than $14,000 extra a year.

Documents obtained by WGN News and The Better Government Association show, for example, in May 2009, Commissioner Beavers reported spending just $162 of his $1200 monthly allowance. On another, he claimed $1900 in expenses over a three month period.

Commissioner Beavers publicly said that if he didn’t use all his expense money, he’d keep it as income. The contigency expenses have long been considered by some to be a personal slush fund on top of their $85,000 annual salaries. But other commissioners said that’s against the law because they can’t just give themselves raises. Tonight, Beavers told WGN News he hadn’t seen the subpoena so he wasn’t going to comment.

After this expense fund came to light recently, the county board voted to lower the monthly amount to less than $1,000 a month and Commissioners are now required to fill out monthly reports, not just annual expense reports.

Cook County Commissioner Tony Peraica had not heard about the subpoena of Beavers but he told WGN News, coincidentally at Tuesday’s County Board meeting, he tried to abolish the entire contingency expense fund his proposal was defeated.