The death of Prince was surrounded with controversies and the investigators are digging deeper to the real cause of his demise. As for the latest update, Arsenio Hall filed a defamation lawsuit against singer Sinead O'Connor for accusations that he was the late icon's drug supplier.

Hall filed the $5 million defamation lawsuit in LA Superior Court on Thursday and said that O'Connor is not in the position to accuse him of anything, writes The Hollywood Reporter. He reportedly went furious over the singer's Facebook post, stating that she is a "desperate, attention-seeker ... now known perhaps as much for her bizarre, unhinged internet rants as for her music."

"Ever since O'Connor posed her malicious and reckless lies about Hall on her 'OFFICIAL Facebook page' (where they have been commented on and forwarded thousands of times), her brazen lies have spread like wildfire across the media throughout the United States and the world," as stated in the complaint brought by lawyers Martin Singer and Lynda Goldman.

Music lovers would know that O'Connor's biggest hit was "Nothing Compares 2 U," which was originally sung by Prince. However, Hall claimed that they are not close friend at all, and she only had met him a couple of times. The copy of the complaint can be viewed on the website.

As for the investigation, U.S. attorney and Drug Enforcement Agency have joined forces with the local authorities for a more seamless investigation. According to CNN, they will help by providing "federal resources and expertise about prescription drug diversion."

Meanwhile, other cause of death like cocaine overdose still lingers to the investigations. Belfast Telegraph revealed that a woman, who was not identified, had a conversation with Prince regarding his cocaine use.

People continue to mourn for his death but hoping that the reason might be revealed soon. Stay tuned as this story develops.