Detectives are investigating whether a young shop assistant, who was fighting for life in hospital last night, might have been poisoned.
The 23-year-old woman remained in a critical but stable condition in Bradford Royal Infirmary last night.
She was taken ill at home, suffering from severe sickness, on Tuesday night and was rushed to hospital.
Medics alerted police because of the circumstances of her illness.
Police are keeping an open mind about the cause of her condition but are considering poisioning as a possibility.
West Yorkshire Police’s Protective Services Department is investigating the incident. Detective Chief Inspector Jim Dunkerley is in charge of the inquiry.
Yesterday police sealed off the Boots the chemist shop in Darley Street, where the woman works, while forensic experts examined the scene. The store was reopened five hours later.
A spokesman said it was too early in the investigation to say whether the incident is suspicious.
The spokesman said: “Inquiries are continuing to establish what happened. We are keeping an open mind until we know the exact nature of what happened.
“Poisoning is one theory, whether it be accidental or deliberate, but it is too early to say.
“The woman was taken to hospital on Tuesday after collapsing at home. The hospital reported it to us because of the circumstances. No other person has been affected.”
No items are thought to have been recovered from the store by police.
Colleagues of the woman remained tight-lipped after the branch re-opened yesterday afternoon, with staff, including the store manager, saying they were aware of the incident but not allowed to comment on it.
A spokesman for Boots UK said last night: “The safety of colleagues and customers is of the utmost importance to us. We are aware of the incident and aiding police with their investigation. We are supporting our colleague and her family during this time.”