The mother of four - who also has children Roisin, 20, Shane, 12, and nine-year-old Yeshua - took to social media to threaten her relatives.
Warning: Article contains coarse language
Sinead O'Connor is suing her family.
The 49-year-old Irish singer - who was reported missing on Monday after failing to return from a bike ride the day before in Wilmette, a suburb about 15 miles north of Chicago, but has now been found staying with friends - has blamed her ex-partner John Reynolds and their son Jake, 28, for her disappearance.
The mother of four - who also has children Roisin, 20, Shane, 12, and nine-year-old Yeshua - took to social media to threaten her relatives.
"None of you will ever see me again because of what you've done. If I manage not to kill myself, you'll be paying the medical costs which have been and will continue to be involved with that, since you were and remain. the chief co-ordinator of my total psychological and emotional destruction.
"And I will still never return to you or any of my four children, because of you. So f***ing live with that. Explain to Shane and Yeshua why Mum vanished. You unchristian, ungrateful, lying, criminal.
"You murdered your mother one way or the other. You drove her from her life so she had to run to another continent just to stay alive. You made her leave her babies and then you left them. YOU are the one who needs a f***ing psychiatrist. All of you.
"I will see you all in court. I want damages. I have been unable to work. I have lost last year's income and this year's. I have had enormous medical expenses, and enormous trauma because of your torturing of me.
"As I said. You f***ing best pray God kills me because unlike my poor mother, I will not let this drop. We are all going to court and we are gonna have this out in full public for once and for all."
Before she disappeared on Sunday Sinead posted a message online directed at her oldest son Jake about her other son Shane, who has been placed with TUSLA child services agency in Ireland.
She wrote: "Jake, kindly go to the court on Tuesday and take custody your brother from Tusla. My lawyer will be making the illegal way yourself and Donal got him into Tusla (lying to the cops etc) known to the judge."
The Donal she refers to is believed to be Shane's father Donal Lunny.
And just days before that, she posted an emotional message to Shane, which read: "Baby, I've been trying to get you out of care but Tusla are being monsters. I have to back off because they are hurting me so badly I get unwell again if I go near them.'
"The best thing I can do is advise you get a solicitor of your own which you are now entitled to because you are 12 and bring a case of your own against Tusla, under the Children's rights clauses of the constitution (sic)."
Where to get help:
• Lifeline: 0800 543 354 (available 24/7) • Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7) • Youth services: (06) 3555 906 • Youthline: 0800 376 633 • Kidsline: 0800 543 754 (available 24/7) • Whatsup: 0800 942 8787 (1pm to 11pm) • The Word • Depression helpline: 0800 111 757 (available 24/7) • Rainbow Youth: (09) 376 4155 • CASPER Suicide Prevention If it is an emergency and you feel like you or someone else is at risk, call 111.