Jasmyn Chan, who died following a hit-and-run collision in Sheffield this morning, has been described as "an active, friendly girl".
Paying tribute to the 14-year-old, Chief Inspector Stuart Walne said: "Jasmyn was an active, friendly girl who was very giving.
"This situation is even more upsetting as the driver didn't stop at the scene."
He added: "The driver may not have intended to cause this collision nor are they likely to have been aware of the extent of the injuries they caused last night.
"However I would urge them to think about the impact on Jasmyn's family, friends and community and please come forward."
He said that investigating officers are working on a number of leads and that people have been giving the police information.
A 12-year-old girl who was seriously injured during the incident is being treated in hospital.
More top news
It will be a dull and damp day today, with heavier and more persistent rain to the northwest and across Wales.
The privatisation of Royal Mail was handled with "considerable professionalism" , says a report from Labour's former City Minister.
Public libraries face "absolute disaster" and should take inspiration from coffee shops to avoid large-scale closures, a report has claimed.