A TROWBRIDGE teenager wept in the dock at the Old Bailey today, after she was found guilty of perverting the course of justice when she tried to help her boyfriend clear up after a grisly murder.

Natalia Darkowska, 18, had been trying to contact Jesse McDonald, 25, for three days while he was enjoying a sex and drugs binge with his transgender victim Naomi Hersi. He has now been convicted of Ms Hersi's murder.

University dropout Jesse McDonald, 25, was looking for excitement when he contacted 36-year-old Ms Hersi through dating website Fabswingers.com, the Old Bailey heard.

After a three-day sexual encounter, McDonald drugged and then stabbed Ms Hersi to death with a knife and a broken bottle at a hotel near Heathrow Airport where he was living.

He then spun a web of lies as he recruited his girlfriend to help clean up, jurors were told.

McDonald accepted causing the fatal injuries but denied murder, claiming he acted in self-defence.

He and Darkowska, from Trowbridge, both denied perverting the course of justice.

A jury deliberated for 17 hours to find them guilty of the charges.

McDonald broke down in tears in the dock and bent over with his head in his hands before hugging his girlfriend, saying "I'm sorry".

Darkowska also wept in the dock.

The court heard that Ms Hersi, whose legal name was Hersi Mohamed Hersi, was an openly transgender woman.

McDonald, who grew up in West Sussex, did well in school and played tennis at county level but turned to dealing drugs and trading in Bitcoins after dropping out of the London School of Economics (LSE)

On March 12, he contacted Ms Hersi within 45 minutes of arriving back at the Heathrow Palace Hotel in Hounslow from visiting his girlfriend.

He drove his BMW to the victim's home in Mill Hill, north-west London, where he stayed for three days before they both went back to the small hotel room in Hounslow.

Throughout the period, McDonald is said to have ignored his girlfriend's increasingly frequent attempts to get in touch with him.

On March 16 he sent her a message which said: "Baby I 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."

He then told her he had "got a big drug dealer" lying across his floor, adding "won't wake up...".

Prosecutor Mark Heywood QC said McDonald had planned to dispose of the body, but his victim was found half-naked, partly covered by a rug on the floor of the small bathroom. She had been stabbed up to 40 times.

While the defendants were cleaning up, McDonald phoned his mother and claimed he had been the victim of a sexual attack and had acted in self defence.

His mother, from Haywards Heath, phoned the police after the conversation.

McDonald also offered his landlord a designer watch if he cleared up his room before confessing he had killed someone, jurors heard. Police who found Ms Hersi's body and the murder weapon tracked MsDonald and Darkowska to a hotel in Teddington where they were arrested.

During his police interview, McDonald continued to claim he had been bound and raped.

Giving evidence, the Brighton-born defendant said he had contacted Ms Hersi online "because I'm a complete idiot".

He said: "Clearly I was looking for something. I'm disappointed in myself.

"At the time I felt open-minded, liberal-minded, whatever you want to call it."

Following his conviction, Detective Inspector Tom Dahri, from Scotland Yard, 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.

"McDonald completely fabricated that he was kept against his will at Naomi's address". He said there was no evidence McDonald had been attacked, adding: "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.

"We are very pleased the jury saw through his tissue of lies.

"Naomi Hersi will be much missed by all those who knew her, especially by her family.

"The investigation team would like to thank the support and guidance of our key partners from the LGBT communities who have provided us with invaluable advice during the investigation."

Angela Moriarty, from the Crown Prosecution Service, said: "This encounter between two strangers who had consumed a quantity of drugs, led to the tragic death of Naomi Hersi.

"McDonald claimed he inflicted the fatal stab wounds in self-defence but the prosecution was able to prove to the jury that this was not the case, and McDonald had willingly spent days with the victim - even going shopping to Sainsbury's and Tescos' stores together."

McDonald was remanded into custody to be sentenced next Friday.

Darkowska, who was granted continued bail, will be sentenced separately on November 16 to allow time for a probation report to be compiled.