MUMBAI: Key mastermind of the 1993 Mumbai blasts case Mustafa Dossa and extradited gangster Abu Salem were on Friday convicted by a special TADA court.

The court has also convicted Tahir Merchant, Riyaz Siddiqui Abdul Rashid Khan and Kareemullah Khan. Abdul Qayyum was acquitted by the court.

While Dossa was convicted on charges of conspiracy and murder under various sections of the IPC besides offences under the TADA Act, the Arms Act and the Explosives Act, Salem was found guilty of transporting weapons from Gujarat to Mumbai ahead of the blasts.

He had also handed over to actor Sanjay Dutt-- who was an accused in the case for illegally possessing weapons-- AK 56 rifles, 250 rounds and some hand grenades at his residence on January 16, 1993. Two days later on January 18, 1993 Salem and two others went to Dutt's house and got back two rifles and some rounds.

Dossa was also found guilty of arranging for the arms and ammunition for the blasts with his brother Mohammed Dossa and making travel arrangements for some of the persons involved to meet absconder mafia don Dawood Ibrahim Kaskar.

Earlier, the court had dropped certain charges against Salem in 2013 after the investigating agency --CBI-- moved a plea, saying those charges were against the extradition treaty between India and Portugal.

Dossa allegedly masterminded the landing of explosives including RDX in India and sent some youth to Pakistan to acquire arms training to execute the blasts.

The dastardly attacks had left 257 dead, 713 persons seriously injured and destroyed properties worth Rs 27 crore.

In the first leg of the trial that concluded in 2007, the TADA court had convicted 100 accused in the case, while 23 persons were acquitted.

The trial of the seven accused -- Abu Salem, Mustafa Dossa, Karimullah Khan, Firoz Abdul Rashid Khan, Riyaz Siddiqui, Tahir Merchant and Abdul Quayyum -- were separated from the main case as they were arrested at the time of conclusion of the main trial.

On March 12, 1993 the country's commercial capital witnessed an unprecedented terrorist attack when a series 12 bomb explosions took place one after another in about a span of two hours.

The blasts took place at Bombay Stock Exchange, Katha Bazaar, Lucky petrol pump near Sena Bhavan, opposite Passport office near Century Bazaar, Fishermen's colony at Mahim Causeway, at basement of Air India Building, Zaveri Bazaar, Hotel Sea Rock, Plaza Theatre, Centaur Hotel (Juhu), Sahar Airport (Bay no.54) and Centaur Hotel (near airport).

This was the first-ever terrorist attack in the world in which RDX (Research Department Explosive i.e cyclotrimethylene trinitramine) was used on such a large-scale after the Second World War.

According to the prosecution, in order to avenge the demolition of Babri Masjid, members of the crime syndicate under the fugitive don Dawood Ibrahim along with other absconding accused Tiger Memon, Mohammed Dossa and Mustafa Dossa hatched a conspiracy to commit terrorist acts in India.

The prosecution said that the object of the crime was to commit terrorist acts with an intent to overawe the Government of India, to strike terror on the people, alienate section of the people and to harm the communal harmony.

It said that the conspirators smuggled fire-arms, ammunitions, detonators, hand grenades and highly explosive substances like RDX into India and stored it.

According to the prosecution, Mustafa Dossa, Tiger Memon and Chhota Shakeel organised training camps in Pakistan and in India to impart and undergo weapon and arms training and handling of explosives. They also sent men from India to Pakistan via Dubai for arms training.

The prosecution also said that the conspirators held 15 meetings before the execution of the blasts.