But in November of 2010, prosecutors sought to expand the scope of their investigation to include a search of Walker's county executive office and the home of Kelly Rindfleisch, Walker's then deputy chief of staff, according to the newly released documents.
The order also allowed the prosecutors to expand the probe to include three other county aides: Nardelli, his chief of staff; Fran McLaughlin, his spokeswoman; and Dorothy Moore, his scheduler.
In the November 1 hearing, two assistant district attorneys asked Judge Neal Nettesheim to approve expanding the investigation, a request the judge approved after the prosecutors detailed emails and communication between Walker's county staff and his campaign.
The search warrants allowed prosecutors to seize "all items of evidence in whatever form and by whatever means they may have been created or storied." The warrant included had hard drives, computers, writings, papers or any photographic form.
Much of the search centered around Rindfleisch, as the search warrant approved by the judge allowed prosecutors to search her car, home and financial records. She was accused of exchanging emails with campaign staff of Walker and of Brett Davis, who was running for lieutenant governor at the time.
The newly released documents were sealed until Court of Appeals Judge Patricia Curley ruled last week the records should be made public, according to the Milwaukee Journal Sentinel. The documents come from Rindfleisch's case file.
Rindfleisch pleaded guilty in 2012 for conducting political business during Walker's 2010 gubernatorial campaign while she was on the county's clock. Reports show she frequently emailed campaign officials using a private email address, as well as a router installed in the county executive office to separate those emails separated from county-related emails.
Walker's political rise
Walker set off a firestorm in January 2011, soon after becoming governor, when he moved to curtail the collective bargaining rights of most Wisconsin state employees.
With majorities in both houses of the legislature, Walker and his GOP allies pushed to limit raises for public employees -- except police and firefighters -- to the rate of inflation, bar unions from deducting dues from workers' paychecks and force them to hold a new certification vote every year.
The bill was signed into law in March of 2011, following weeks of protests at the state capitol building in Madison. A group of Democratic lawmakers also briefly fled the state to delay a vote on the bill. Walker's efforts and the furor that followed put him under the national political spotlight and made him a hero to many tea party supporters and other grassroots conservative activists.
The law was upheld in state courts, but the episode sparked an effort to recall Walker. He won the 2012 recall election.
What else is in the emails?
By May 2010, employees of Walker's county executive office appear to have realized using the personal emails during the day was something they needed to stop.
Archer emailed a group of county and campaign executives -- including Walker -- on May 18, 2010, to say that she will "no longer be checking this email account during the work day" in light of "recent events."
"We discussed this among CEX [county executive] staff this morning and were unable to find alternative," Archer writes. "We can discuss more on Friday AM."
In testimony to a judge, investigator David Budde said this email was a "direct admission that Archer was using private email during the work day."
"The significance of this email is that it shows that the people addressed on this email are acting in concert with the county executive staff to find alternative ways to communicate using private email during the workday," Budde said.