A 17-year-old girl killed in an east London park was stabbed once in the back by a teenage attacker who did not say a word to her, police have said.

Jodie Chesney, 17, was attacked at about 9.25pm on Friday in St Neot’s Road in Harold Hill and died an hour later.

The Metropolitan police said on Sunday that she had been with five friends in the park listening to music and socialising. Witnesses saw two males in the park who left at 9pm. The two males and the group Jodie was with did not speak to each other or interact.

“Around 30 minutes later the pair returned to the park and walked straight towards the group, where one of the males stabbed Jodie once in the back. Nothing was said by the two suspects, who ran off in the direction of Retford Road,” the Met said.

“The suspect who attacked Jodie is described as a black male aged in his late teens. There is no further description of him at this stage, nor is there any description of the other male.”

Jodie Chesney was a Scout and took part in a televised Remembrance commemoration in November last year. Photograph: PA

DCI Dave Whellams, who is leading the investigation, urged witnesses to contact police: “There has been excellent support from the local community and a number of people have shared information with police, but there will be other witnesses and people with information that may prove crucial,” he said.

“Although the description of the suspect is limited, I am certain that people will have seen the two males hanging around the park or running away from the scene, or will otherwise have noticed something suspicious. I need those people to call me.”

Jodie’s uncle Dave Chesney paid tribute to her and also urged witnesses to come forward. “This was a totally random and unprovoked attack on a beautiful, lovely and quirky young girl with her whole life in front of her,” he said.

Dave Chesney told ITV News that Jodie was the daughter of his youngest brother, Pete, adding: “We value your support and prayers at this time especially for our brother Pete, his wife, Jo, and Jodie’s sister, Lucy. Also for the friends that were with her at the time.”

Jodie had visited Downing Street while a Scout and taken part in a televised Remembrance commemoration in November last year.

Police said a postmortem examination carried out on Sunday at East Ham mortuary established the cause of death as trauma and haemorrhage.