The sick fan who threatened to shoot his little sister if rapper J. Cole ignored his Twitter.com message has issued an apology to the star after police launched an investigation into the online prank. The Work Out hitmaker was left stunned on Monday night (17Jun13) when he saw the photo of the man holding a BB gun to his sibling's head alongside the note, "@JColeNC retweet me and I'll buy (his new album) Born Sinner. Don't retweet me and I'll kill my lil (sic) sister." Cole promptly obeyed and expressed his shock over the bold move with his fans, writing, "Wildest s**t I ever seen on twitter (sic)." The offending tweet, posted from an account reportedly registered in Saudi Arabia, has since been deleted from the hip-hop star's page, but it had already been picked up by gossip bloggers and U.S. authorities have since discovered the message came from a 19 year old in Texas. Local officials at the New Braunfels Police Department are currently investigating the incident and a representative tells TMZ.com, "(The suspect) is cooperating and it seems this was just a bad lapse in judgment. For now this is still an open investigation, and for the time being no charges are being filed." The man, who has not been identified, has also spoken out to express his regret over his silly behaviour: "I'd like to apologize to America for the photo and to put J. Cole in that position. It was all a joke." "It was an unloaded BB gun and my sister was in on it. I only tweeted it because I didn't expect a response. Mr. Cole please don't sue me. I want to formally apologise more to J. Cole... My mum made me delete my twitter (sic) until I fixed it."