The prosecution may not use a statement obtained from a defendant who has been granted immunity, but evidence that is demonstrated to be obtained independently from defendant’s statement may be introduced in the prosecution’s case in chief. Appellant, a former police officer, was prosecuted for assaulting an arrestee and filing a false report regarding the incident. The police department hired an independent investigator to investigate the incident. In the course of the investigation of the incident, defendant gave a compelled statement, after being advised it would not be used against him at trial. At trial, the investigator testified that he was a former police officer who, after viewing a video of part of the incident, concluded that appellant had control of the arrestee, such that excessive force was not required. The court rejected appellant’s argument that the evidence from the investigator violated Kastigar v. United States (1972) 406 U.S. 441, regarding the treatment of witnesses exposed to compelled statements. Once a defendant establishes that he has provided a statement under a grant of immunity, prosecuting authorities have the burden of showing by a preponderance that evidence is not “tainted” by the compelled statement. Here, in basing his opinion as to the use of force by appellant, the investigator relied on sources independent from appellant’s statement. Prior to testifying, he was directed to base his opinion only on what he saw on the video, as supported by his experience and knowledge of control techniques acquired before he viewed the video. The court also rejected appellant’s argument that the investigator’s testimony was excessively prejudicial under Evidence Code section 352 because the defense could not effectively cross-examine the investigator without introducing the statement because any potential bias of the investigator could be introduced without disclosure of the statement. Despite its holding, the court was troubled by the prosecution’s decision to create a potential for error by calling the investigator, when his evidence could have just as easily been provided by another witness.