Federal prosecutors putting alleged leaders of an ultraviolent street gang on trial want to stop defense attorneys from asking a Chicago police veteran about the notorious Homan Square police facility.

Jury selection is already underway in the trial of six alleged Hobos gang members at the Dirksen Federal Courthouse. Opening statements are expected later this week. Once testimony begins, prosecutors are expected to call Nicholas Roti to testify as an expert about Chicago street gangs.

Roti is the former chief of the organized crime bureau for the Chicago Police Department.

However, defense attorneys have signaled their intention to cross-examine Roti about an article published by The Guardian newspaper in March 2015, records show. The article tied Roti’s retirement that month to allegations published earlier by The Guardian that Homan Square is the domestic law enforcement equivalent of a CIA “black site.”

CPD has denied the claim.

Assistant U.S. Attorney Timothy Storino wrote in a motion Saturday that the article is irrelevant, and he described its attempt to link Roti to the Homan Square allegations as “at best tenuous.” The article noted that Roti ran a unit based at Homan Square, and he retired shortly before the filing of a civil rights lawsuit aimed at shutting it down.

That lawsuit was filed on behalf of three men who said they were handcuffed to a bar on a cell wall for eight or nine hours, denied access to an attorney and bathroom, and were not read their Miranda rights. It has been dismissed with prejudice, records show.

“The article makes no allegation against Mr. Roti; instead, the article notes only the timing of Mr. Roti’s departure from CPD and attempts to tie it to claims of misconduct by CPD generally,” Storino wrote. “It is these claims of misconduct that will carry the danger of unfair prejudice because they are unrelated to this case and simply seek to smear by association the testifying witness.”

Prosecutors say the Hobos, a so-called “super gang” formed by members of the Gangster Disciples, Black Disciples and other gangs, terrorized Chicago’s South and West sides between 2004 and 2013. Among the defendants on trial are alleged Hobo leader Gregory “Bowlegs” Chester and alleged killer Paris Poe.

The feds say they’ve tied the gang to nine murders.