Earlier, these cases were being probed by the Punjab Police.
An NIA spokesman said in a statement that the cases relate to the killings of Hindu leaders and a priest, and firing at an RSS 'shakha' (centre).
The first case relates to the firing at the Rashtriya Swayamsevak Sangh (RSS) 'shakha' in Ludhiana city on January 19 last year, the spokesman said. Two people riding a motorcycle and wearing monkey caps fired a single shot at the 'shakha'.
Thirty-five-year-old Arora, a hosiery unit owner, was at Basti Jodhewal Chowk in his car waiting for someone when the two motorcycle-borne men fired at him and fled. He was rushed to a local hospital and survived the bid on his life.
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Another case relates to the killing of Shiv Sena leader Durga Dass Gupta in Khanna in Punjab on April 23 last year.
The two cases of killings of Amit Sharma, the publicity manager of Sri Hindu Takht, and two followers of the quasi- religious cult Dera Sacha Sauda were also taken over by the NIA.
The NIA also took over the case of killing of the pastor of a local church, Sultan Masih, who was shot dead by two assailants in Ludhiana in July this year.
All these cases were claimed to have been cracked by the Punjab Police in the first week of November when Chief Minister Amarinder Singh said that four people had been arrested in connection with the killings of Sharma, Gupta, Masih in Ludhiana and Dera Sacha Sauda followers.
The chief minister had claimed the killings and other terror-related activities were part of a major conspiracy to fan communal disturbance and destabilise the state and was hatched by the ISI, external snooping agency of neighbouring Pakistan.
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