Democratic state Sen. Laura Murphy and Republican challenger Mel Thillens fended off accusations from one another about being beholden to party leaders and special interests during a public debate in Des Plaines.

The campaign for the 28th Senate District seat has grown in visibility in recent weeks with TV commercials, radio spots and mailers funded by party money and super PACs.

During a debate Wednesday night at Des Plaines City Hall, Murphy criticized Thillens for receiving “dark money” from Liberty Principles PAC, which released a commercial last week claiming House Speaker Mike Madigan has helped fund Murphy’s campaign.

Murphy said she hasn’t received “one cent” from Madigan or the Democratic Party of Illinois, of which he is chairman, and her campaign filed a cease-and-desist order to have the commercial taken off the airwaves.

Murphy has received $368,972 to date from a separate account controlled by Senate President John Cullerton, the Senate Democratic Victory Fund, according to the Illinois Campaign for Political Reform, which tracks campaign expenditures.

Thillens said he doesn’t communicate with Liberty Principles, backed by conservative radio host Dan Proft, but is happy for the support of those taking an interest in his campaign.

Campaign finance records show the group has spent $313,663 in support of Thillens since March.

Murphy, a one-time Des Plaines alderman appointed to the Senate seat vacated by Dan Kotowski a year ago, said she’s stood up to party leadership by supporting reforms to the way district maps are drawn and introducing a bill to limit terms of legislative leaders.

If elected to a full 4-year term, Murphy said she would likely have to vote for Cullerton to maintain his leadership position since “we probably won’t have any options.”

Thillens, a Park Ridge park board commissioner, also supports so-called fair maps but says term limits should apply to all legislators. He pledged not to serve more than 10 years if elected.

“She’s been part of the machine that’s been getting politicians elected for her entire life,” Thillens said of Murphy.

Murphy retorted, “My opponent woke up on third base one day and thought he hit a triple. The rest of us have to go to bat each day and work for each base.”

The 28th District includes portions of Des Plaines, Elk Grove Village, Park Ridge, Roselle, Rosemont and Schaumburg.