A former top aide to Wisconsin Gov. Scott Walker has filed a federal civil rights lawsuit against the Milwaukee County District Attorney's Office, charging that its long-running "John Doe" probe into Walker's political activities was a partisan witch hunt that violated the aide's constitutional rights.

Cindy Archer, formerly Walker's deputy administration secretary, filed the suit in federal court Wednesday. It names District Attorney John Chisholm and four other officials in his office as defendants.

Chisholm started a special probe of Walker in 2010, initially to investigate financial improprieties by his staff when he was Milwaukee County executive. The probe was expanded several times before being shut down by a judge in 2013. Archer became one of its targets, and law enforcement officials, including FBI agents, acting under Chisholm's authority, raided her home in 2011. The lawsuit says the probe was an abuse of authority done because Chisholm was a Democrat who opposed Walker's political agenda.

"This is America, and in America we don't let the authorities raid people's homes and treat them like criminals because of their political beliefs and associations," said Archer's counsel, David B. Rivkin Jr. of the law firm Baker & Hostetler. "That's why we have a Bill of Rights: to stop things like this John Doe investigation from happening."

The lawsuit seeks unspecified monetary damages from the defendants. Others listed as defendants include David Robles, Bruce Landgraf, Robert Stelter and David Budde.

Chisholm's office did not respond to a request from comment.

Wisconsin law allows prosecutors to launch criminal probes, known as "John Doe investigations," that allow them to subpoena witnesses and evidence without first showing probable cause that a crime was committed. The idea is to determine whether probable cause exists to file charges. The proceedings are meant to be secret and subjects are forbidden from discussing them publicly.

Walker's political allies have said that Chisholm used the investigation as a political weapon to embarrass the governor by fishing for information unrelated to the supposed point of the probe and making details public through leaks to the media. Chisholm knew those touched by the probe would be unable to publicly speak in the defense.

"The purpose of these actions was retaliation. Defendant Chisholm informed subordinates in his office that it was his duty to 'stop' Gov. Walker from reforming public-sector unions in Wisconsin," the lawsuit says.

Archer was the key architect of the reforms in question, which limited collective bargaining by public-sector unions to only wages. The reforms also allowed public-sector workers to opt out of paying union dues and required the unions to hold annual recertification votes or lose state recognition.

The reforms have resulted in an exodus of workers from the unions in the years since the reforms passed, severely limiting the unions' political and financial clout.

The lawsuit quotes an ex-staffer saying that the district attorney's office walls were covered with posters declaring solidarity with unions, that several staffers participated in the 2011 recall election against Walker and that Chisholm himself expressed anger over the governor's agenda.

Chisholm's actions included an early morning raid on Archer's home in 2011 during which her computers were confiscated and her home ransacked while she was forced to remain there and be interrogated — all despite the fact that no charges had been filed against her.

The lawsuit describes the raid in harrowing detail, claiming that law enforcement authorities entered the suburban house with guns drawn and a battering ram ready. Archer feared her dogs would be shot for barking. Both she and her girlfriend were observed getting dressed by the officers, the latter forced to exit a shower and put on clothes in front of investigators.

Any evidence obtained through the raid could have been obtained through a simple subpoena, Archer's lawyers argued. "There was no reason to believe that drawn guns or even armed officers were required to protect the officers from the two unarmed women who lived there," the lawsuit stated.

The lawsuit also states that Chisholm's office tipped off the Milwaukee Journal Sentinel about the raid, an action that was made with the district attorney's "express or implied approval."

However, Jason Stein, one of the two reporters who covered the incident for the paper, indicated to the right-leaning WisconsinWatchdog website in an April interview that he was alerted by Archer's neighbors after the raid began.

"[The] home was being raided in plain sight on the east side of Madison, where many of the state's most liberal residents live. The real mystery, to me, was why only one reporter showed up," Stein said.

Charges were never filed against Archer. Two years later a judge ordered the probe closed, stating the district attorney's office had not shown probable cause that crimes had been committed.

Archer was nevertheless forced to step down from her position in Walker's administration and was the subject of numerous media reports after the raid implying she was about to be charged with criminal violations. The suit claims the investigation derailed her career, strained her finances and she became depressed and suicidal as a consequence.