Police said the explosion appeared to be an accident. It severely damaged at least 15 houses in a crowded working-class area in Mumbai's northwestern suburb of Jogeshwari.
"Five people were killed on the spot and one girl died in the hospital," Ahmad Javed, joint commissioner of police, said, adding “From preliminary investigations, it looks like an accident.”
Police and witnesses said Thursday's explosion took place at about 3:15 am (21.45 GMT Wednesday) in Rajman Chawl, located on a low hill with narrow, winding lanes and rows of brick houses.
"The explosion took place in the house of Dilnawaz Khan. This man supplied firecrackers and explosives for use in films," Satyapal Singh, a joint commissioner of police, said.
"He had a large quantity of explosives stored in his house. This is absolutely illegal," he said, adding "We have detained his nephew for questioning and our experts have gone to a storehouse where Khan stored explosives."
|"This man supplied firecrackers and explosives for use in films."|
-Joint Commissioner of Police Satyapal Singh
Dilnawaz, his wife, daughter and brother-in-law were all killed in the explosion.
"The explosion was so powerful that Dilnawaz's hand was blown off and fell outside my house. His daughter's body was blown about 40 metres away," said Gajanand Pawar, who lives opposite Khan. "My house has also been damaged, but none of us was badly injured."
Police said the explosion could not be linked to the Ghatkopar bus blast, but investigations would focus on whether Khan, in addition to film units, supplied explosives to armed groups.
A bomb exploded on a bus in Ghatkopar, a northeastern suburb of Mumbai, on Monday, killing two people.