By Brendan O'Brien
MILWAUKEE (Reuters) - A conservative organization in Wisconsin filed a federal lawsuit against state investigators on Monday, saying its members' civil rights were violated during an ongoing secret probe into campaign financing, court documents showed.
The Wisconsin Club for Growth filed the lawsuit in U.S. District Court for the Eastern District of Wisconsin, accusing investigators of violating its members' freedom of speech and association and equal protection rights.
The organization is asking the court to halt the 17-month probe into what the Wall Street Journal has described as claims of illegal coordination between conservative special interest groups and political campaigns.
The group contends in the complaint that investigators have infringed on its members' civil rights by sidelining them from political activities during the 2014 legislative and election cycles due to the probe.
It charges the current investigation and an earlier secret probe were politically driven, noting that both were initiated by Milwaukee County District Attorney John Chisholm, a Democrat.
The current investigation is the second such probe Chisholm has aimed at conservatives since Republican Governor Scott Walker took office in 2011.
The first investigation began in May 2010 and resulted in charges filed against six people, including four of Walker's aides.
(Reporting by Brendan O'Brien; Editing by Cynthia Johnston and Mohammad Zargham)