The independent charity Crimestoppers is now offering a £3,000 reward for information given to them which leads to the arrest of wanted man Kieran Williams.
The 18-year-old is wanted in connection with an incident in which a shotgun was discharged from a vehicle in the Hartcliffe area of Bristol on 19 May.
Officers would also like to speak to him about a separate incident in which a 17-year-old boy was stabbed in the Brislington area of the city on 29 May.
Williams is known to frequent the south Bristol area and is described as white, with brown hair, blue eyes, and around 6ft tall.
If seen, the public are advised not to approach him.
Detective Inspector Laura Miller said: “We understand people are sometimes reluctant to speak directly to police and so we’re grateful for Crimestoppers for its support.
“The most important thing in this instance is for us to locate Williams and question him about two serious incidents.
“Public safety is our utmost priority and there are times when we really don’t mind where information has come from.”
You can contact Crimestoppers 100 per cent anonymously on 0800 555 111 or via their Anonymous Online Form.
No personal details are taken, information cannot be traced or recorded and you will not go to court or have to speak to police when contacting Crimestoppers.
If you are happy to speak to police please call 999 and quote log number 639 of 29 May. Alternatively if you know where he may be, call 101.