Detectives in New York are investigating inscriptions of “deny”, “defend” and “depose” on bullet casings left at the scene of the murder of the UnitedHealth Group executive Brian Thompson, according to a person familiar with the case.

As a sprawling manhunt to find the killer entered a second day, the New York Police Department released photographs on X on Thursday morning of a person wanted for questioning about the homicide. The NYPD, which is still searching for the motive behind the shooting, said “all indications are that it was a premeditated, targeted attack”.

One of the photographs, which the NYPD published online alongside an appeal to the public for any information relating to the case, shows a hoodie-clad man smiling at a counter.