The emails which threatened to blow up a five-star hotel located near the city's international airport terminal in suburban Andheri, was traced to Kenya, police said on Monday.
In the second week of January, the management of Hotel Leela received two email threats to blow up the structure, following which searches were carried out for two days by the Bomb Detection and Disposal Squad.
However, nothing suspicious was found on both the occasions.
"Investigation into the case revealed that the IP address from which the emails were sent was traced to Kenya," Additional Commissioner of Police (Crime) Deven Bharti told PTI refusing divulge further details.
Another police official said "it seems that it was the work of a disgruntled customer. He may not be happy with the service of the hotel. However, we are yet to reach a final conclusion."
The culprit had sent two emails demanding a sum of $1.3 lakh, otherwise he would blow up the hotel.
The identity of the sender was not revealed and nor was the place where the payment was to be made.
Additional security has been provided at the hotel.
Meanwhile, US consulate officials today met police officials in connection with the six US victims who were killed in Mumbai terror attacks.
"The meeting was in connecting with the US victims who lost their lives during the attacks. It has nothing to do with investigations," Deven Bharti said.