An electrician is expected to be locked up in a secure mental unit after a jury ruled he killed his wife.
Abdelaziz El Msseyah, of Godwin Road, Margate, slashed the throat of Souad Bellaha, 56, after claiming she was Lucifer and had poisoned him.
The 58-year-old was facing a charge of murder - but a judge decided he was unfit to plead because he is suffering from dementia.
Now a jury at Maidstone Crown Court has ruled he "carried out the murderous act".
He is facing a sentence under the Mental Health Act, which will mean he will remain in a secure unit until the Home Secretary rules he is safe to be released back into the community.
El Msseyah was arrested after police were called to his wife's home in January 2021. They found her body slumped next to the bath with her throat cut and the knife lying on her chest.
Prosecutor Johnathan Polney said the 999 operator asked: "What's happened?" and El Msseyah replied: "I killed my ex-wife, my wife."
The operator asked: "Why did you kill your wife?"
El Msseyah said: "There are many reasons. A lot of reasons for it."
The prosecutor told the jury: "The police knocked on the front door and the defendant opened it and was told to go to the living room.
"They noticed blood on the floor, spatter marks and arrested him."
The prosecutor said officers then searched him and found a note in his back pocket.
El Msseyah said: "I have written this to police before I done it (sic)."
The note read in part: "I know very well that nobody will understand why I reacted in this way because they don't know how she is (truth, Lucifer, evil)
"She will suck all your energy and throw you in the bin. This is my story and I don't know how many before me.
"I decided to stop this and not to harm anyone any more. I lived in hell with her during 12 years.
"I was manipulated from those years. I knew something wrong with her behaviour. I was in blindly (in) love with her because she (treated) me very good..then we married and she brought me in UK.
"Perfect prey, the victim. Easy to manipulate. I was entrapped.."
He added he believed his ex-wife was "sucking energy" from him, adding: "Each time she is enraged. Pushed me to believe that I am wrong every time and provoke me all the time..harassment me all the time..blackmail me..all that.
"Then she make me believe something wrong in my brain and I have to get scanned.
"The scan revealed I am unspecified dementia..total domination..total destruction of moral, spiritual, psychology all the ways."
He claimed that following that he suffered chest problems, adding: "Give poison..I still resist and serve her fully. She never happy. I was blind and misinformed.
"I was isolated until I have crisis".
He called his ex-wife "the beast" and beat her over her body with an earthenware water jug before slashing her throat.
The jury took less than 20 minutes to conclude El Msseyah had carried out the murderous act. He would have faced a life sentence but for his serious mental health problems.
Sentence was adjourned for a month, pending further psychiatric reports. He was remanded to a secure psychiatric unit in Maidstone.
Afterwards, Judge Philip Statman praised police officers DC Jeff Brunger, DS Richard Allingham, DCI Kath Way, DC Chris Brett and paramedic Caroline Cripps for their professional approach to "what must have been a shocking and horrific scene".