Frances Bean Cobain's Ex-Husband Sues Courtney Love for Attempted Murder for Guitar

5:40 AM PT 5/30 -- John Nazarian tells TMZ he was nowhere near Silva's house at the time this incident allegedly happened.

Frances Bean's ex-husband is not done with her family, because he's now suing Courtney Love claiming she entered into a conspiracy with several people to break into his home, beat him up, kidnap him and try to murder him so they could gain possession of Kurt Cobain's legendary guitar.

Isaiah Silva claims in a new lawsuit, in the early hours of June 3, 2016, Sam Lutfi -- the one involved in the Britney Spears drama years ago -- along with 2 other guys burglarized, robbed, assaulted, sexually battered, kidnapped and attempted to murder him at his West Hollywood Home.

Silva says the goal was to get the guitar that was made famous on "MTV Unplugged" that he claims was gifted to him by Frances Bean.

Silva claims the group also injured his mother.

And the allegations go on. Silva claims Lutfi provided narcotics and illicit benzodiazepines to Frances and Courtney.

Frances settled her divorce with Isaiah and agreed to give him the famous guitar just to get him out of her life, but clearly that didn't work.

Silva is also suing John Nazarian, actor Ross Butler and musician Michael Schenk ... claiming they were all involved in the conspiracy. BTW, he alleges they made their way inside his house by pounding on the front door and yelling, 'Police, open up!!!" and "LAPD, open the f******* door!!!" And he claims, Lutfi grabbed Silva's genitals through his pants, moved to within inches of his face and whispered, "Listen fa***t, calm the f*** down or we'll drag you upstairs and take turns f****** you."

He says he was hurt during the ordeal.

Silva is asking for unspecified damages.

We reached out to Courtney's manager ... so far no word back.