Detective Superintendent Heather Pearson, of North Yorkshire Police said:
As a result of the incident a criminal investigation is underway. Officers are deployed to support the 83-year-old woman who is being cared for by family members.
"A number of enquiries are ongoing including tracing people who can assist.
"Detectives would like to speak to anyone who can assist in establishing a picture of the events leading up to the assault and ask that they contact York CID as soon as possible."
Any witnesses are being asked to contact North Yorkshire Police on 101.
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Kerrie brings you Saturday night's forecast for the Tyne Tees region
North Yorkshire Police say they have arrested 41 people in the first nine days of this year's drink and drug driving campaign.
Gusty winds over hills. Mainly dry with a cooler night ahead