Two media publications, RadarOnline.com and the National Enquirer, have refused to hand over audio recordings which Los Angeles police believe pertain to their investigation involving Charlie Sheen.

As previously reported, the LAPD confirmed on April 6 that the actor is, in fact, being investigated for threatening to kill his ex.

Both RadarOnline and the Enquirer published reports about the investigation and quoted from audio allegedly of Sheen making threats, but neither has made the audio public. Investigators want to hear any recordings, although the two publications have refused to give them the evidence requested. Even after police served a search warrant to the entertainment sites’ parent company, American Media Inc., the tabloids said they will not hand over anything as such warrants cannot be used against media organizations.

Although the LAPD did not name the alleged victim, it has been reported that it is Sheen’s ex-fiancée, Scottine Ross a.k.a. Brett Rossi. She and the former Anger Management star were engaged in 2014.

Sheen revealed last year that he is HIV-positive.