Steven Campbell, referred to in court documents as “Soupy Sales,” testified in federal court Wednesday afternoon as the man who allegedly plotted to kidnap, torture, extort and murder him — an ex-Chicago cop named Steven Mandell — sat just a few yards away at a table with his attorneys.

Jurors appeared riveted as the man they had heard referred to repeatedly in secretly recorded conversations between Mandell and government informant George Michael answered questions from a federal prosecutor and Mandell’s attorney for about a half hour.

Campbell, a Riverside businessman with extensive property holdings on Ogden Avenue in Brookfield, was questioned about his properties and about a suspicious letter he received in October 2011.

The handwritten note inquiring about a property in the 8900 block of Ogden Avenue in Brookfield was signed “Steve,” and a business card left with the note bore the name “Steven Mandell.”

Campbell explained how he became suspicious of the note after calling the number on the business card and talking twice to the man on the other end. Asked by Campbell how he knew his home address, the man reportedly told him that he had visited his office and, when he wasn’t there, got the information from the owners of a body shop across the street. Campbell said the business referred to as his “office” is simply a garage. He owns the building where the body shop is located.

The man also mentioned Campbell’s “friend, Peraica,” a reference to former Cook County Commissioner Tony Peraica.

Peraica is a neighbor of Campbell’s, and Campbell testified that he had stored some of Peraica’s old campaign signs behind one of his buildings.

Campbell testified that he thought it odd someone would have connected all of those properties to him and would have acquired his home address, which he said was unknown to the body shop owner.

“It raised my radar from yellow to orange,” Campbell said in response to a question about the letter by federal prosecutor Diane MacArthur.

The days after receiving the letter and business card, Campbell testified that he personally turned them both over to Riverside Police Chief Thomas Weitzel.

Mandell’s attorney, Keith Spielfogel, attempted to question Campbell’s recollection of when he received the note, but Campbell was firm in claiming he received in in October 2011, nine months prior to Mandell meeting Michael. Spielfogel also had Campbell confirm that Mandell had never attempted to contact him after the letter.

But Mandell in 2012 allegedly found someone else to do that for him — Michael, a real estate broker on Chicago’s Northwest Side.

In secretly recorded conversations between Mandell and Michael in September and October of 2012, there’s reference to Mandell having tried and failed to get Campbell “out.”

Michael, who was wearing a wire for the FBI, ultimately was able to set up a meeting with Campbell on Oct. 25, 2012. At that time, Mandell and an associate named Gary Engel allegedly were going to snatch Campbell and take him to a place they dubbed “Club Med” — an office building in the 5300 block of West Devon Avenue—converted into a torture chamber where they would force Campbell to reveal places where he hid cash and turn over his real estate holdings.

The two were arrested by FBI agents as they showed up at Michaels’ office in the 6300 block of North Milwaukee Avenue that evening.

Mandell’s attorney has stated Mandell never intended to carry out the plot.

The government is expected to rest its case Thursday. Mandell is expected to testify, possibly on Friday.