A man has been arrested on suspicion of sending 26,000 texts in one day pretending to be delivery firm Hermes and asking for people’s bank details.
Police swooped on a hotel room in the Ibis hotel in Charles Street, Manchester, on Thursday afternoon, according to the Manchester Evening News.
Hotel staff had reported seeing suspicious activity in the room including a man with a large number of cables in a bag.
Officers arrested a 21-year-old man from Manchester and found a laptop and other devices.
The suspect was being interviewed on suspicion of committing fraud and remains in police custody.
Detectives believe the kit was used as part of a sophisticated 'phishing' scam.
Analysis showed more than 44,000 mobile phone contacts were stored on the devices found in the room.
26,000 texts pretending to be from the courier firm Hermes were sent out in a single 24 hour period.
The texts were all asking the recipient for bank details because of a missed delivery.
Police Community Support Officers went to the hotel at 3.30pm on Thursday and later detectives from the City of Manchester division and GMP's Cybercrime Team seized the electronic equipment found in the room.
As an investigation was launched, Greater Manchester Police issued a fresh warning to people to beware of so-called 'Phishing' scams, where bogus emails or texts are sent out in an effort to trick recipients into handing over their bank details.
Online fraud costs billions in the UK and has risen during the pandemic.
Detective Inspector Mark Astbury, of GMP's City of Manchester Central division, said: "What we have uncovered here are potentially the components of a highly sophisticated and authentic scam that I know many people not just in Greater Manchester but across the country have been potential victims of in recent weeks and months.
"We have a man in custody and various items of potential evidence that we have seized and this is due to the initiative of the hotel staff, who acted on their suspicions, and the subsequent response from our neighbourhood officers in the city centre.”
He added: "These are the very early stages of what promises to be a complex and dynamic investigation, and I would like to take the opportunity to remind the public to ensure they keep remaining alert to the daily risks that unscrupulous cyber criminals pose to them by sending these fraudulent messages."