This depends on what “publicly available” means. As far as I know, no jurisdiction actively disseminates investigation material, such as recorded interviews with suspects, to the public in the same way that the authorities publish laws and judicial decisions.
When evidence of a police interview is adduced in open court, it becomes “public” in the sense that the information can generally be published (for example, by a journalist sitting in the courtroom). This freedom can overcome confidentiality obligations that may have applied to the information before it was admitted in evidence.
But court records are not “public” in the sense that they can be easily found on a freely accessible database. The courts still control access to the record and use this control to charge fees and limit the record’s dissemination in the interests of justice. It is uncommon for courts to grant non-party or media access to sensitive exhibits (eg. where widespread publication would unreasonably harm a witness or party’s privacy), even if this information was “published” to those physically present in the courtroom which was open to the public.
Many jurisdictions have detailed legislation governing access to court documents, as well as legally enforceable disclosure requests using subpoenae or freedom of information laws. To receive a more precise answer, you need to specify the jurisdiction and your reason for requesting the document.