Police in the Indian city of Bombay (Mumbai) have charged four people in connection with bomb attacks last Monday in which 52 people died.
The blasts caused massive damage
The suspects, who include a couple and their 16-year-old daughter, were also charged with another bomb blast on 28 July.
All four are members of the minority Muslim community and are local to Bombay, India's financial capital, police say.
Police are also questioning several other suspects about last week's twin attacks, in which 140 people were wounded.
News of the arrests came as Bombay was on a heightened state of alert for the opening of a popular Hindu festival marking the birth of the God Ganesh.
The authorities have given few details about the four who were charged under India's tough anti-terror laws.
But they say they belong to a little-known group allegedly motivated by a sense of grievance about last year's communal violence in the neighbouring state of Gujarat.
It is not clear if the accused had links with other Islamic militant groups.
One, named as Mohammed Hanif, was described as having worked in Dubai.
His wife, Fahimida, and daughter, Farheen, had accompanied him to the Gateway of India where one of the two blasts occurred, police say.
Both women and a fourth suspect, Arshad Ansari, were produced in court in Bombay on Monday and were remanded in custody until later this month.
Mr Hanif is in hospital and did not appear.
Police said they found several vital clues leading to the arrests, but admitted that some key questions remained unanswered - not least the source of the powerful explosives used.
Detectives have indicated that they received vital information in their hunt for the bombers from the driver of one of the two taxis in which the explosives were planted.
The suspects were remanded in custody until later this month
Shortly after the bomb blasts, Indian officials laid the blame on Muslim militant groups, one of which is based in neighbouring Pakistan.
They said the type of explosives used linked the attacks to an Islamic Kashmiri separatist organisation, Lashkar-e-Toiba.
Pakistan was quick to condemn the bombings on Monday.