Hussein, who was also convicted of possessing a knife, was convicted after around eight hours of deliberations. He stood facing the jury and crossed his arms as the verdicts were delivered in front of the victims' parents.
Hussein set up an online lottery account the day before the killings using a photograph of his passport, the court heard. On June 7, the jury heard he spent £17.50 on ten Mega Millions bets and two Mega Millions syndicate bets - none of which came in.
The killer may have been attracted to the sisters because they were dancing around fairy lights they had brought to the park with them, the jury heard.
Mr Glasgow QC told the Old Bailey Hussein attempted to access Miss Henry’s phone more than 130 times between 1.26am and 3.48am, at which point it was dumped in a pond in the park along with Miss Smallman’s handset.
During the time he had the phone, the device’s data reveals that he walked 2km as he attempted to clean up the scene by putting bloodied blankets in bins, the court heard.
Families of both the defendant and the victims, including the sisters' mother, were in court.
He will be sentenced at a later date.
Danyal Hussein guilty of stabbing sisters in Wembley park in 'pact with devil'