A chef who admitted fatally stabbing a teaching assistant had been in a "bad mood" and wanted to hurt someone, a court heard yesterday.
Robert Cusworth, 25, attacked Sally Garwood as she walked her dog in a playing field near her Buckinghamshire home.
He pleaded guilty at Reading Crown Court yesterday to murdering thirty-four-year-old Mrs Garwood on 11 July.
The Crown Prosecution Service described the attack as "utterly senseless" and praised a nine-year-old boy whose evidence helped lead to Cusworth being charged.
Lawyer Carl Barker said after the hearing: "The reason Robert Cusworth murdered Sally Garwood is impossible to comprehend. As he told the police, he was in a bad mood and he purchased a knife with the sole intention of hurting someone.
"Sally Garwood was an innocent young woman who had done nothing to provoke or invite the attack.
"This was a chilling and utterly senseless murder which has taken the life of a young woman and devastated the lives of her family."
Her husband, Simon, said: "She was such a kind, amazingly happy person who even smiled in her sleep. I cannot believe I am spending the rest of my life without her."
Judge John Reddihough remanded Cusworth in custody and adjourned sentencing until 29 January. A psychological assessment will be carried out.