Danyal Hussein lay in wait before repeatedly stabbing Nicole Smallman and Bibaa Henry, jurors heard.
A man accused of killing two sisters “promised to sacrifice” women in order to win the lottery, a court has heard.
Danyal Hussein, 19, repeatedly stabbed Nicole Smallman, 27, and Bibaa Henry, 46, in a Wembley park on 6 June last year, the Old Bailey was told.
Police who searched his room found a document purporting to be an agreement between the teenager and a demon, the prosecution said.
Mr Hussein, of Blackheath, south-east London, denies murder.
Ms Henry was stabbed eight times while Ms Smallman was stabbed 28 times. They had been in Fryent Country Park celebrating Ms Henry’s birthday.
Opening the case, prosecutor Oliver Glasgow QC said of the defendant: “He promised to sacrifice women in order to win the lottery and not to be suspected of the crimes he had committed.
“It would appear that the defendant had confidence that his plan would work since following the fatal attacks upon Bibaa Henry and Nicole Smallman, the defendant purchased several lottery tickets and there were three lottery tickets folded up inside the note.
“As it turned out, the demon did not come good on the bargain, since not only did the defendant not win the lottery but the police identified all the evidence that links him to these two murders.”
When the sisters failed to come home, their loved ones became concerned and some of their friends went to the park to look for them.
Police were alerted after the women’s glasses were discovered and soon after a knife was found lying in the grass.
A trail of flattened grass led to the “shocking” discovery of the bodies, Mr Glasgow said.
“The bodies of Bibaa Henry and Nicole Smallman lay on their sides; they were top to toe and their limbs were intertwined. Both of them had been repeatedly stabbed and they were clearly dead.
“The attack upon them had been as savage as it was devastating.”
Mr Glasgow suggested Ms Henry was taken by surprise and overpowered first, then Ms Smallman tried to fight off her attacker.
“Once the two sisters had been brutally murdered, their killer dragged their bodies across the grass and concealed them in a hedgerow,” he said.
The court heard that a combination of forensic evidence and CCTV footage led police to Hussein.
His DNA was at the scene, on the bodies of the victims and on a bloodstained knife found nearby, the jury heard.
The teenager, who had bought a set of knives from Asda in the days before the attack, went to hospital the day after the killings, the Old Bailey was told. He had cuts to his hand from a knife.
The trial, which is set to last four weeks, continues.
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