A note pledging blood in exchange for making a woman fall "deeply in love" was found in the bedroom of a man accused of murdering two sisters in a park, a court has heard.
Danyal Hussein, 19, is accused of launching a ferocious knife attack on sisters Bibaa Henry, 46, and Nicole Smallman, 27, in the early hours of 6 June last year.
The siblings, who had been celebrating Ms Henry's birthday, were found dead in bushes in Fryent Country Park in north London the following day.
Jurors at the Old Bailey heard how the pieces of the investigation came together on 30 June last year after a DNA breakthrough.
Following Hussein's arrest on 1 July last year, police recovered some handwritten notes from his bedroom at an address in southeast London.
Detective Sergeant Rob Dodds told jurors how a paper pouch contained a pendant and some papers.
One of them was addressed to Queen Byleth and signed Danyal.
One side of the paper read:
- Making (name redacted) fall deeply in love with me to the point where she isn't interested sexually nor romantically in anybody but me.
- To make (name redacted) believe and see that I am the only one for her.
- Make (name redacted) fall so deeply in love with me where she shows and expresses her love for me.
- Making me more attractive to women romantically."
The other side of the sheet read:
- Every two weeks burn insense [sic] in your name, offer some sweet drink, offer chocolate
- Buy more red candles
- Offer some blood
I agree to uphold the requests made and to uphold my side of the agreement.
Signed by Danyal"
The court heard that the name of a woman referred to in the note had been blanked out of the exhibit seen by jurors.
DS Dodds said inquiries established that at Hussein's school there was a young lady with the same name.
Jurors have previously heard how a handwritten note to another demon allegedly signed in Hussein's blood was also seized.
Detective Chief Inspector Simon Harding, who led the inquiry, told how media appeals had been issued for information about anyone who had cut their hand, after a quantity of blood not belonging to the victims was identified.
Swabs produced male DNA - labelled Unknown One - that was not on any databases, DCI Harding said.
However, the database did produced a familial DNA link on 30 June last year, the court heard.
Investigators found that teenager Danyal Hussein was a member of the same family and that his father lived near the park.
DCI Harding told the court: "One of my officers deployed to do some research around purchases of knife blocks piped up straight away and said 'I've got him buying knives in Asda a couple of days before'."
CCTV covering the defendant's Wembley address was recovered showing a male returning at around 4am on the morning of the killings.
Mr Harding said: "This was really, really quick. In an hour and a half we had everything."
Hussein, of Guy Barnett Grove, Blackheath, southeast London, has denied two counts of murder and possessing a knife.