Should be pretty obvious, I think, but it had to be litigated. From Chasnoff v. Mokwa (Mo. Cir. Ct. June 11, 2014), an excerpt of the findings of fact:

1. Wendell Ishmon, Thomas Kranz, Phillip Menendez, Joseph Somogye, [NAMES OMITTED], Michael Deeba, Daniel Disterhaupt, Philip Edmond, Michael Ehnes, Edward Kuntz, and Joseph Spiess are or were at all times material hereto commissioned police officers employed by the Board of Police Commissioners of the City of St. Louis.
2. During October 2006, the baseball World Series was played in St. Louis. The Ishmon plaintiffs were assigned to, or supervised, a special detail deployed to prevent ticket scalping, i.e., the sale of World Series tickets at prices above their stated price.
3. Several persons arrested for ticket scalping filed complaints that the arresting officers appropriated the arrestee’s money and World Series tickets. These complaints induced the Police Department to conduct an “internal affairs” investigation. The investigation disclosed that a number of World Series tickets seized from arrestees were utilized by other persons and then placed in the evidence storage area of the vice/narcotics division….
6. The [Internal Affairs Division] interviewed each of the Ishmon plaintiffs in the course of investigating the World Series ticket complaints. The IAD investigators presented each officer with the “advice of rights” quoted above, which is based on Garrity v. New Jersey, 385 U.S. 493 (1967), and the subsequent interviews are known in the Police Department as “Garrity statements.” Each Ishmon plaintiff signed the advice of rights form. Some, but not all, of the Ishmon plaintiffs were represented by counsel during the interviews. None of the interviewees invoked his right to remain silent….
8. Although the recorded interviews in this case vary, the Court finds that at no time did the IAD investigators promise or represent that the so-called Garrity statements would not become public record or would not be disclosed for legitimate purposes. The Ishmon plaintiffs understood that the statements were being obtained for “internal use only,” but in actuality, the consistent representation was only that the statement could not be used in any subsequent criminal prosecution. The oral statements of the IAD investigators regarding the potential use of the Garrity statements did not vary materially from the written “advice of rights” form, which makes no representation that the Police Department will treat the recorded statement as secret. Notwithstanding the evidence of the custom regarding use and disclosure of “Garrity statements” within the Police Department, the Court finds that, in fact, no promises of secrecy were given in this case.
9. As a result of the IAD investigation of the World Series ticket complaints, 16 Ishmon plaintiffs were disciplined, with the penalties ranging from written reprimand to varying suspensions and demotions in rank. It does not appear from the record that any officer contested the discipline imposed. The findings of the IAD investigation were that the officers in question failed to observe rules for proper handling of evidence, engaged in conduct unbecoming an officer, or violated department procedures. No officer under investigation was charged with giving false information to the IAD. The Court finds that the officers were forthright in their statements to the IAD concerning the improper use of the seized World Series tickets….
And here’s an excerpt from the court’s legal analysis: