Beal, of Moore Street, appeared before two magistrates on Monday and spoke only to confirm her age and address.
She was arrested at a Cumbria hotel just after midnight on Wednesday – the same day Northamptonshire Police began their detailed search.
Forensic officers and specialist search teams, including a cadaver dog, were deployed before Saturday’s discovery.
Police said the remains of Mr Billingham, who was described as a 42-year-old officer believed to be missing, were expected to be taken to Leicester for an examination by a Home Office pathologist.
Beal was accompanied by a lone female dock officer during the two-minute hearing at Northampton Magistrates’ Court.
She was told she was not entitled to apply for bail and will appear at the town’s crown court on Tuesday.
Beal, who was wearing a grey round-necked sweatshirt, was remanded into custody.