As fate would have it, Metropolitan police officer Alan Thompson was having a drink at The Magdala. He found Ellis still holding the gun and cautioned her. A few minutes later, police from the Hampstead Police Station arrived, arrested Ellis and took her into custody on 10 April 1955. David Blakely was rushed to the New End Hospital but pronounced dead on arrival.
At 11pm on 10 April 1955, witnessed by three senior CID officers, Ellis made a statement admitting to shooting Blakely. The officers present were Superintendent Leonard Crawford, Detective Chief Inspector Leslie Davies and Detective Inspector Peter Gill.
At 12.30pm on 11 April 1955, Ellis was charged with murder. She appeared briefly at  Hampstead Magistrates Court on 12 April 1955, before being taken to the all-female Holloway Prison in Islington, to await her sentence of death by hanging, less than a month away, as Prisoner 9656.