Courtney Love has been accused of plotting to have her daughter's ex-husband killed in a bid to retrieve a guitar that belonged to Kurt Cobain.
Isaiah Silva, a musician, was married to Frances Bean Cobain, Love and Cobain's only child, from 2014. Ms Cobain filed for divorce in March 2016.
Under the terms of their divorce, Silva was entitled to keep a highly valuable 1959 Martin D-18E guitar the Nirvana frontman played during an MTV 'Unplugged' performance in 1993.
During the divorce proceedings, Miss Cobain had argued the guitar should remain in her family, but Silva successfully claimed it was his as she had given it to him as a gift.
Now Silva (33) has alleged that Love, her manager Sam Lutfi - Britney Spears's former manager - and a group of men attempted to kidnap and kill him in June 2016 to get the guitar back.
He filed a 329-page civil suit in a Los Angeles court seeking unspecified damages. He claimed: "The primary objective of their conspiracy was to locate and take possession of a guitar believed to be worth millions of dollars, which was gifted to Silva, by Frances, on January 8, 2014, six months prior to their June marriage."
He alleged Mr Lutfi and two other men "did burglarise, rob, assault, batter, sexually batter, kidnap, and attempt to murder" him at his house in West Hollywood.
According to the complaint, men at the door shouted: "Police, open up." and "LAPD, open the door." Silva claimed that once inside, Mr Lutfi grabbed his genitals through his clothes.
He claimed the men were going to kidnap him to end any legal claims he was making for spousal support, and to get the guitar back.
The trio allegedly forced him out of his home and into a black Cadillac Escalade while a friend called the police.
When they arrived, Mr Lutfi "hurriedly concocted a false story intended to prevent LAPD from arresting them".
Love and her co-defendants are understood to be ready to fight "all the way" over the allegations.