A joint team of the National Investigation Agency or NIA and the Uttar Pradesh Police, carrying out searches in Ghaziabad today in connection with the killing of an RSS leader in Punjab, was fired upon and pelted with stones by a mob, leading to injury to a policeman, the agency said. Giving details, a NIA spokesperson said that during the course of investigation into the killing of RSS leader Ravinder Gosain in Ludhiana, investigators came across the names of certain suspected arm smugglers who had supplied firearms to the accused in Punjab.