Delhi Police investigators have announced the arrest of a terrorist cell that they claim was responsible for a string of nationwide attacks last year — raising fears that Pakistan-based jihadist groups may be preparing for a renewed escalation of operations against India.

The Delhi Police's élite Special Cell announced on Wednesday that it had held six men, including Karachi-based Jaish-e-Muhammad operative Muhammad Adil, on the suspicion of having carried out three major attacks last year: a shooting at Delhi's historic Jama Masjid in September; the serial bombs outside Bangalore's Chinnaswami Stadium in April; and the bombing of the German Bakery in Pune in February.

Fugitive Indian Mujahideen commander Muhammad Zarar Siddibapa — a Karnataka resident also known by the alias Yasin Bhatkal and the commander of the cell, who is wanted for his alleged role in a string of urban bombings that began in 2005 — however escaped arrest, the police said.

Adil is alleged to have had past relationships with both the Jaish-e-Muhammad and organised crime groups. He, the police said, was living under cover in Madhubani, Bihar, since 2010, when he was despatched to India by Indian Mujahideen commanders in Karachi to aid Siddibapa's cell.

Bihar residents Mohammad Siddiqi, Irshad Khan, Gauhar Aziz Khomani, Gayur Jamali and Abdur Rahman were held in separate raids in New Delhi and Chennai. The Delhi Police said they had recovered several kg of explosives, ammunition, two assault rifles and a pistol from a safe house used by the cell.

The case is the second involving a Pakistan national in recent weeks. Earlier, the National Investigation Agency said fugitive Jammu and Kashmir-based terror commander Ghulam Sarwar, a resident of Pakistan occupied Kashmir, had carried out the bombing of the Delhi High Court in September.

Sarwar, interestingly, possessed fake documents identifying him as a Bihar resident, and travelled to meet still-unidentified contacts in the State — raising the prospect that he may have had links to the cell held in Delhi.

Wednesday's arrests are the third in a series linked to the Pune bombings —all at apparent odds with each other. Maharashtra prosecutors had earlier charged local resident Himayat Baig with having carried out the bombing in Pune, naming Siddibapa as his commander. Elements of their account, though, sit ill with the Delhi Police's findings. For example, Maharashtra Police investigators said Baig was paid to source bomb-making equipment to fabricate an explosive device at his cyber-café. The discovery of a bomb-factory in Delhi, though, puts this version in some doubt.

Union Home Minister P. Chidambaram told reporters on Wednesday that the six arrested men were suspected of having been “involved in February 13, 2010 German Bakery blast in Pune.”

Earlier this year, though, Mr Chidambaram told Parliament the Maharashtra Police had solved the Pune bombing — following on from an earlier faux pax in which he complimented investigators on having arrested Siddibapa's older brother, Abdul Samad Siddibapa, in connection with the case. Abdul Samad Siddibapa was later cleared of all charges and released.

(With inputs from Vinay Kumar in New Delhi and Amruta Byatnal in Pune.)

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