. >>> and remembering a popular entertainer on johnny carson, merv griffin. viewers loved him and his psychic powers. >> david: good evening. we begin tonight with the breaking news. the new turn in the murder of that ceo in new york city. tonight, the nypd revealing they now have forensic evidence tying suspect luigi mangione to the crime. and tonight, sources telling abc news mangione's family has now started to speak with investigators. tonight, mangione remains in a pennsylvania jail after that outburst 24 hours ago, refusing extradition to new york. what authorities have revealed about the gun now, and about a notebook full of mangione's writings. tonight, detectives consider it to be a confession. also this evening, why authorities are growing increasingly concerned about people on social media appearing to celebrate the suspect. abc's senior investigative correspondent aaron katersky leading us off again tonight. >> completely out of touch and an insult to the intelligence of the american people. >> reporter: accused killer luigi mangione may be fighti

fighting fires and creating >>> and remembering a popular entertainer on johnny carson, merv griffin. viewers loved him and his psychic powers. >>> good evening. we begin tonight with the breaking news. the new turn in the murder of that ceo in new york city. growing increasingly concerned about people on social media appearing to celebrate the suspect. correspondent aaron leading us off tonight. >> reporter: luigi mangione may be fighting extradition in pennsylvania, but investigators are building a murder case against him in new york, and tonight, they say, they have their first forensic match. from fingerprints on a water bottle and snack bar wrapper near the crime scene to the ghost gun police say was used to murder unitedhealthcare ceo brian thompson. >> we were able to match that gun to the three shell casings that we found in midtown at the scene of the homicide. >> reporter: detectives also now have what they consider to be a confession, a spiral notebook that sources say contains plans for how to kill thompson. what do you do, one passage allegedly read, you whack the ceo at