Colombo: The defence ministry in Sri Lanka and acting police chief Chandana Wickramaratne stated almost all and plotters and executors involved in the April 21 terror attacks have either been arrested or are dead.

Reuters quoted Wickramaratne as saying, “There were also two people among that group of plotters who are experts in bombs and those two are dead now,” adding, “they had stored part of the explosives for future attacks and we have confiscated all of this.”

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However, reports suggest that i nvestigators are still tracking down 10 more key players associated with plotting the attacks that killed more than 250 people, including 42 foreigners and 45 children.

Reuters reported that sources told them about investigations that show there were another 8 to 10 people who attended meetings with the other plotters.

Police spokesman Ruwan Gunesekera said that $40 million worth assets belonging to bombers and plotters were frozen. The bombers were all associated with the Easter Sunday attacks on Sri Lanka.

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Sri Lankan authorities have now said they believe that the bombings carried out by two little-known domestic Islamist groups, the National Tawheed Jamaath (NTJ) and Jamathei Millathu Ibrahim (JMI). Islamic State has claimed responsibility, but Lankan authorities are still probing that angle.

Investigators from eight countries, including the US Federal Bureau of Investigation and Interpol, are helping Sri Lanka with the investigation.

Investigators are currently checking whether the plotters had any foreign help, the sources of their funds and if the bombers had any credible link to Islamic State.

Sri Lankan authorities on Monday discovered a facility believed to be used as a training centre by the suicide bombers prior to the terror attacks on churches and luxury hotels on Easter Sunday that killed more than 250 people.

The two-storey building was discovered in the Blackpool area in Nuwara Eliya. Details of this facility had surfaced during questioning of few suspects who were arrested in connection with the NTJ in Sainthamaruthu, Kalmunai, the Times Online reported.

According to preliminary investigations, the final training session which was attended by Zahran took place on April 17 - four days prior to the deadly Easter attacks.

Zahran, the mastermind behind the Easter blasts, is believed to have led the attack on the Shangri-La hotel and was accompanied by a second bomber identified as Ilham Ahmed Ibrahim. He was killed inside the hotel where he blew himself up.