The complainant, Arun Gulati learnt about the gang from messages being circulated on WhatsApp, police said.
"Few days ago Gulati had received a message along with the photos on his WhatsApp informing about a gang in the city hoodwinking people by posing as fake Tata Power employees," police said.
When four persons, claiming to be Tata Power employees, visited Gulati's house in East Shalimar Bagh on Monday and asked him to shell out Rs 1,000 for faulty meter, he got suspicious and asked his sister to check the pictures on WhatsApp.
Arrested accused have been identified as Ashok Verma (35), Sunil (28) and Gaurav Gujral (23). Police are on the lookout for the fourth accused Y Gupta alias Sunil Gupta, who had managed to flee, police said.
Fake I-cards, purportedly issued by Tata Power, Rs 1,000 which they had taken from Gulati, and a knife were recovered from them, police said.