The accused were identified as Micheal Kallu Ibe (28), Ugwu Uchha Nna (39), Anthony Ogbobe (36) and Okafor Onyeka (24) (all Nigerians) and Kishan Makwana (45).
DCP (Zone 1) Rajendra Shisve said the accused had formed a bogus company and placed an online advertisement for sale of a laptop.
The complainant, who lives in Dubai, paid Rs 45,000 online for it, but got no delivery, he added.
From the information recovered from a laptop and mobiles seized from the place in south Mumbai's Colaba where the accused lived, police suspect that they have duped many persons by offering electronic products, jobs, lottery prizes or escort girls, etc., online.