A university dropout has been found guilty of the "cold and calculating" murder of a transgender woman after a sex and drugs binge.
Jesse McDonald, 25, drugged and then stabbed Naomi Hersi to death with a knife and a broken bottle at a hotel near Heathrow Airport where he was living.
He had met the 36-year-old through dating website FabSwingers.com, the Old Bailey heard.
McDonald then spun a web of lies as he recruited his 18-year-old girlfriend, Natalia Darkowska, to help clean up, jurors were told.
Prosecutor Mark Heywood QC told the court how McDonald planned to dispose the body, but Ms Hersi was found half-naked and partly covered by a rug on the floor of the bathroom.
Image:Naomi Hersi was stabbed to death at a hotel near HeathrowMcDonald accepted causing the fatal injuries but denied murder - claiming he acted in self-defence.
He and Darkowska, from Trowbridge in Wiltshire, both denied perverting the course of justice.
After deliberating for 17 hours, the jury found them guilty of the charges.
McDonald broke down in tears when the verdict was delivered, telling his girlfriend: "I'm sorry".
Image:Jesse McDonald was found guilty of murderThe court heard that Ms Hersi, whose legal name was Hersi Mohamed, was an openly transgender woman.
McDonald, from West Sussex, is a former grade A student and played tennis at county level before getting into drug-dealing and selling Bitcoins after dropping out of the London School of Economics (LSE).
On 12 March, he contacted Ms Hersi via his account on FabSwingers.com behind his girlfriend's back, and the pair had a seven-minute phone conversation where he admitted to looking for a sexual encounter.
Image:CCTV showed Jesse McDonald and Naomi Hersi at a Tesco storeHe later drove his BMW to the victim's home in Mill Hill, northwest London, where he stayed for three days before they both went back to the small hotel room in Hounslow.
McDonald is said to have ignored his girlfriend's attempts to get in touch with him but on 16 March sent her a message which said: "Baby I have been a f****** idiot".
Another read: "I love u so much. Not cheated x. Got addicted to a nasty drug I had never met before."
Image:Natalia Darkowska was found guilty of perverting the course of justiceHe then told her he had "got a big drug dealer" lying across his floor, adding "won't wake up... massive black guy".
Ms Hersi was dead by the time Darkowska arrived, but she helped clean up the blood that was all over the room rather than phoning the police.
McDonald then phoned his mother and claimed he had been chained up for days - drugged with GHB and repeatedly raped.
Image:CCTV of McDonald and Darkowska checked into another hotel after the killingHe alleged that he had stabbed Ms Hersi up to 40 times in belief she was going to smother him with a pillow.
His mother phoned the police after the conversation.
Jurors heard how McDonald offered his landlord a designer watch if he cleared up his room before confessing he had killed someone.
During his police interview, he continued to claim he had been bound and raped, but later said he had contacted Ms Hersi "because I'm a complete idiot".
He said: "Clearly I was looking for something, I wanted to get out. I don't know, it is not uncommon for me to have done something like this in the past. I'm disappointed in myself.
Image:McDonald and Darkowska (back to camera, wearing hat) being arrested"At the time I felt open-minded, liberal-minded, whatever you want to call it."
Following his conviction, Detective Inspector Tom Dahri said: "From day one of this murder, McDonald has spun lie after lie and tarnished the name of the victim by calling her some of the vilest names in front of her family.
"This was all just smoke and mirrors to make himself look like a victim, when in fact he is a cold and calculated killer who dragged his girlfriend in to help him clear up his mess."
McDonald was remanded into custody to be sentenced next Friday.
Darkowska, who was granted continued bail, will be sentenced separately on 16 November.