Police responded to reports of gun shots heard in the East Drive area of Queen’s Park, Brighton, around 10.30pm on Sunday (August 4).
Officers said they attended the area and the circumstances remain ‘under investigation’.
Anyone with information, or who saw or heard anything, is asked to contact police on 999 or online quoting serial 1712 of 04/08.
You can also contact the independent charity Crimestoppers anonymously on 0800 555 111 or report it online.
Police added that a warrant was executed at an address in Birdham Road, Moulsecoomb, on Monday evening (August 5).
Officers said a 42-year-old woman from Brighton was arrested on suspicion of assisting an offender and failing to comply with conditions of a shotgun certificate.
She remains in police custody at this stage, said police.