Detectives are hunting for a man dressed all in black who broke into a Fylde coast nursing home and entered a resident's room before being disturbed by staff.
Police say they are investigating a "sexual offence" after the man allegedly forced entry to the New Thursby nursing home, on Clifton Drive North, St Annes, in the early hours of Sunday (August 4).
It is not clear what offence is believed to have been committed but Lancashire Police said the victim is being cared for by professionals.
Officers were called just before 5am after a member of staff at the home found the intruder in a resident's room.
The suspect is thought to have broken in through a ground floor window, escaping the same way when he was spotted.
Det Insp Jamie Lillystone of Blackpool Police, said: “This is a very concerning incident but I would like to reassure people that we are doing everything in our power to find the person responsible including working with a number of specialist units.
“We have a team of detectives working on the investigation and patrols have been stepped up the area. We do not want to concern people but would like to take this opportunity to remind people to make sure they secure windows and doors.
“The victim is being cared for by professionals and is being supported by specialist officers. Their family have been made aware.
“If you have any information at all that could help with our investigation – we need to hear from you. If you were in the area at around 5am and saw anything suspicious, or have any CCTV or dash cam footage that may be useful, please contact us."
Crime scene investigators were on the scene on Sunday, while a police cordon was put up around the home. A blue sheet was up outside one of the windows.
Witnesses reported seeing "four or five" police vehicles at the scene shortly after noon, with forensic investigators in white suits working close to the front of the property.
The New Thursby declined to comment on the situation.