Broadway musical “Chicago” has launched an investigation after friends of a cast member claimed he killed himself because he was “bullied” by the show’s directors.

Pals of Jeff Loeffelholz — who had been a member of the cast for 22 years — started a campaign called Justice for Jeff after Loeffelholz committed suicide, claiming that the production’s director Walter Bobbie and musical director Leslie Stifelman wanted Loeffelholz out of the long-running production but that his contract wouldn’t allow them to fire him.

The group claims that the pair put Loeffelholz, a standby member of the cast, through a tortuous rehearsal on June 22 in an attempt to get him to quit the show, forcing him to sing the same song over and over and telling him, “You always do it wrong.”

The campaign’s blog, Justice For Jeffrey, claims that the account was based on notes that Loeffelholz made after the incident. Loeffelholz died a week later, on June 29. Now Page Six has learned that the producers of the show have hired attorney Judd Burstein to look into Loeffelholz’s situation.

In a statement, Burstein told us, “The producers of ‘Chicago’ are devastated by Jeff Loeffelholz’s death. The producers are taking this matter very seriously, and are fully committed to finding out exactly what transpired. To that end, I have been retained to conduct an exhaustive investigation on an expedited basis.”

Bobbie added: “I am saddened by Jeff’s tragic passing, for him and for his family.” Stifelman didn’t get back to us.

A Broadway insider told us it’s behavior that is known too well on the Great White Way.

“No one can directly blame anyone for something like suicide, but this treatment is kind of like an old-school Broadway scenario where there seems to be a disposable amount of talent that allows people to treat people like this,” said a source. “When you’re loyal to a show like that, it’s not celebrated. It can actually make you unhireable. It’s a strange thing.”