Police have released an e-fit image as part of investigations into an attempted robbery and assault at Hartsholme Park in Lincoln.
The incident took place on June 10 at around 7.15pm when a man described as in his 20s, of skinny build and around five foot six inches tall was reported to have assaulted a woman in her 40s.
She had refused to hand over jewellery or a mobile phone and was left with a minor injury to her cheek, police said.
He is described as having blond, unkept hair and was wearing a grey t-shirt.
Anyone who recognises the e-fit image should call 101 quoting incident number 405 of June 10.
To report anonymously, people can also call Crimestoppers on 0800 555111.