Three people have been detained for suspected involvement in a scheme to sell online food-ordering discounts, Shanghai police said yesterday.

The detainees allegedly used illegally-acquired mobile phone numbers to register with local online food ordering services. The discounts these services offer to newly-registered users were later sold by the detained trio, according to police.

Officers in Changning District started investigating the matter in January after noticing ads on the Internet for such discounts.

The three were eventually located and apprehended in Baoshan and Jiading districts.

They allegedly admitted to using software to produce fake International Mobile Equipment Identity numbers on illegally-acquired mobile phone numbers and then used the data to register with food delivery websites.

Three other suspects from a technology company in Tianjin which produced the software have also been put under detention. Police say the software is able to modify computer data and exploit loopholes in mobile phones, computers and other information systems.

A suspect in Tianjin surnamed Zeng, who founded the company, has allegedly admitted to profiting over 2 million yuan (US$300,000) from the software.

Eight other suspects who allegedly sold the software on behalf of the company were also detained in Guangdong, Shandong, Jiangsu and Liaoning provinces.

Shanghai police say the number of cases involving computer systems is up significantly this year, compared with 2017.