A 16-year-old boy killed a young mother during an argument over drugs money, a court has heard.
Paige Gibson, 23, was knifed in the chest outside her flat in Halifax, West Yorkshire, in the early hours of 7 June, Bradford Crown Court heard.
A prosecutor told jurors the teenager was "increasingly angry" after she failed to give him money which he and his friends wanted for drugs.
The 16-year-old, who cannot be named for legal reason, denies murder.
The boy and his friends had been taking drugs in a flat in the same complex as Miss Gibson's home at Weavers Brook in Ovenden, the trial has heard.
He gave his phone to Miss Gibson, while his friend gave her his tablet, on the basis she would sell them and give them money for more drugs.
The mother-of-three lived a "squalid life, dependent on drugs" and used crack cocaine and cannabis, the court was told.
But when she returned to the flat in the early hours without the phone and tablet or any money, the boy shouted "watch Paige, watch" and stabbed her, jurors heard.
Prosecutor Nicholas Campbell QC said Miss Gibson had seemed "intoxicated by drink and drugs in a way that she had not been when she left".
He said the boy was arrested an hour after the attack, despite trying to cover his tracks.
Jurors were told they would hear about "the world of drug-taking in Halifax" and how "lives were ruined".
Mr Campbell said the boy had a "troubled life" and was sometimes "not such a pleasure to be around".
The trial continues.