13 year-old Casey Kearney died on Valentines' Day after she was stabbed in Elmfield Park in Doncaster.
Police want people who were seen near the park just after 1pm that day to contact them.
More top news
Friends of a Rotherham teenager, who is battling leukaemia, are walking 63 miles to Cleethorpes - to help raise funds for treatment in US.
Often very windy with rain or showers
Often very windy, especially as we head into Sunday, with rain or showers. Met Office 'Be Aware' warnings have been issued