Nottinghamshire Police have launched an investigation following multiple incidents of people being spiked by "something sharp" while on nights out.
The force said a number of the victims reported being spiked by some sort of injection and have reported effects “consistent with a substance being administered”.
Spiking is the act of adding alcohol or a drug to food or drink without the knowledge of the person who consumes it.
Police said they had received 44 spiking reports since 4 September, including 12 with “something sharp” as opposed to contaminated alcoholic drinks.
The first of the 12 was reported on 2 October, and one victim suffered an injury which could be consistent with a needle.
It comes as a 20-year-old man was released on bail after being arrested on suspicion of possession of Class A and Class B drugs and cause to administer poison or noxious thing with intent to injure, aggrieve and annoy following an incident in Nottingham's Lower Parliament Street on 16 October.
The arrest came several days after a young Derby woman was rushed to hospital after allegedly being spiked with a needle in Nottingham’s Stealth nightclub.
Ellie Simpson said her sister spent the night in hospital after the ordeal at Stealth on 12 October, when she felt a "pinching or scratching sensation" on the back of her arm.
The young woman does not remember anything from that moment on and had to be treated by on site medics, before later spending the night in A&E on a drip.
Ms Simpson has said that her sister, who studies in Nottingham but is from Derby, has been left seriously shaken by the experience.
She said: "She's OK now, but she's still really shaken up and afraid to go out.
"They were trying to leave the club and on the way out she felt something on the back of her arm, a pinching or scratching sensation, and she can't remember anything after that.
Watch: Student feels 'violated' after suspected spiking injection
"The police took urine samples so I don't know if they will be able to find anything.”
Other spiking incidents in parts of England, Scotland and Northern Ireland have also been reported in recent months.
An investigation has been launched into another incident in which a woman said she was attacked with a needle inside Fever and Boutique in Exeter on 16 October, while University of Nottingham student Zara Owen, 19, told how she believes she was spiked with an injection during a night-out with friends.
Ms Owen, from Surrey, said she blacked out soon after arriving at Pryzm nightclub last Monday, telling BBC Breakfast she “found a pin prick in my leg which was the epicentre of all pain”.
Nottinghamshire Police said it is planning to deploy more officers to the city centre over the next few weekends.
Superintendent Kathryn Craner said: “Over the last few months we have seen an increase in reports where people believe that drugs may have been put in their drink – that’s due to the fact that they have experienced a distinctly different feeling to their normal reaction to alcohol.
“But we’ve also received a small number of reports where people are telling us, as Zara has, that this has been associated with a pain or a mark on a part of their body, scratching sensation, and as though they have been physically spiked.”
If someone has been spiked, it is recommended to tell a member of staff and to ensure someone stays with the victim, calling an ambulance if their condition deteriorates.
It is important to ensure they do not travel on their own, or drink more alcohol.
A petition for greater security checks for nightclubs has reached over 125,000 signatures, surpassing the threshold needed for the matter to be debated in Parliament.
Police have also been asked to urgently assess the scale of drink spiking at nightclubs and parties.
Home secretary Priti Patel has asked forces for an update after some said they had seen more spiking incidents in recent months, while groups from more than 30 universities around the UK have joined an online campaign calling for the boycott of nightclubs.
Campaigners are seeking “tangible” changes to make them safer, such as covers/stoppers for drinks, better training for staff and more rigorous searches of clubbers.
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