Washington (CNN) -- A 21-month investigation into allegations that the Federal Air Marshal Service has a hostile work environment -- rife with discrimination and retaliation -- has concluded that no "widespread" problem exists, according to an internal government e-mail obtained by CNN.
But, investigators also concluded, a large number of air marshals think those problems exist.
The e-mail is the first glimpse into the long-awaited investigative report, which is scheduled to be released to the public on February 9.
Whistle-blowers in the air marshal's Orlando, Florida, field office triggered the investigation in early 2010 when they alleged that supervisors used a "Jeopardy!"-style whiteboard to demean and ridicule rank-and-file officers. The board contained derogatory terms to allude to gays, lesbians and African-Americans, they said.
But the investigation grew to include other field offices and other accusations, and the Department of Homeland Security's internal e-mail Tuesday said Office of Inspector General investigators have interviewed more than 300 DHS employees.
While investigators have remained silent about their work, air marshals contacted by CNN say they provided evidence of a wide range of misconduct, including a supervisor who ran a private security business while at work, supervisors who perjured themselves in sworn testimony against subordinates, and instances of favoritism, racism, sexism and discrimination.
A Federal Air Marshal Service spokeswoman declined to comment on the pending report and government e-mail Tuesday. But several air marshals said they are eager to read the report, and say they will dispute any conclusion that discrimination and retaliation are not widespread.
"We're going to tear the report apart," one air marshal, who asked not to be identified, said Tuesday. "We're going to take and review the report and we're going to look at our conclusions, because we know what we gave them."
The internal DHS e-mail summarizes the report's findings.
"The (OIG) concluded that there was no widespread discrimination or retaliation within (the Federal Air Marshal Service)," it says. "However, the report does suggest that a large segment of our workforce feels that retaliation and discrimination exists."
Supervisors have a responsibility to "dispel" the perception that the service is rife with discrimination and retaliation, it continues.
In addition to the normal investigative techniques, the OIG took the unusual step of surveying the air marshal workforce. The survey asked air marshals if favoritism ever played a role in promotions, job evaluations and mission assignments; whether air marshals have ever been discriminated against or harassed on the job; and whether they feel they can report misconduct without fear of retaliation.
In August 2011, the Department of Homeland Security declined a CNN Freedom of Information Act request for the survey results, saying that the documents involved an ongoing investigation. It also said the results could reveal the total number of air marshals, which is classified.
A House committee has scheduled a hearing on the air marshals on Feb. 16.