The 16-year-old, identified only as girl X, posted a picture of Brianna on Snapchat after she was found in Culcheth Linear Park, near Warrington, on the afternoon of 11 February this year.

With the caption "Rest in peace" next to dove emojis, she wrote: "Brianna was one of the best people I have ever met and such an amazing friend it's so f****** sickening what got done to her."

Girl X and boy Y, who is also 16, are on trial at Manchester Crown Court accused of murdering Brianna, a transgender 16-year-old from Birchwood, in Warrington.

The pair, who were both 15 at the time and cannot be named because of their age, deny murder and are blaming each other, the jury has been told.

A 101 call made to police by girl X's mother at around 5pm the day after Brianna's death was played to the jury today.

Girl X told police she and boy Y had been with Brianna in the park, but the victim had then gone off with a 17-year-old boy from Manchester, who owned a car.

Jurors were shown the body-worn camera footage of the moment officers, wearing balaclavas and body armour, entered the homes of the teenagers around two-and-a-half hours later to simultaneously arrest them on suspicion of murder.

Girl X is seen standing on the landing at the top of the stairs as she is arrested, cautioned and handcuffed.

She is heard asking an officer: "How come I'm a suspect? Is it because I was the last person to see her alive?"

Boy Y is seen on the landing outside his bedroom, kneeling down as officers handcuff him, before he tells them: "I can explain."

Read more:
Jurors played 999 call made by dogwalker
Footage shows Brianna leaving home before she was stabbed

Earlier, the court saw footage of boy Y getting the bus home after Brianna's stabbing, with his hood up and sleeves over his hands.

Prosecutor Deanna Heer KC said his internet history showed him accessing websites with advice on breathing exercises for stress and getting help for anxiety.

Girl X later sent him a message saying: "Do you have anxiety about getting caught?"

"Probably," he replied.

Girl X said: "You're not going to get caught don't worry, police are s**** here."

The trial continues on Monday.