Pakistan-based Jaish-e-Mohammed militants, who carried an audacious attack on the makeshift temple at Ayodhya in July this year, had entered the country from Bangladesh.
"The threat from neighbouring Bangladesh is growing and the probe into the recent attack on Ayodhya shows that the militants had entered into India from there," a senior police official said while making a presentation before Prime Minister Manmohan Singh during a conference of directors and inspectors-general of police.
The sources investigating the case said the five militants had come to West Bengal after which they had changed their base to the national capital by moving in smaller groups.
It is suspected that some more militants could be involved in the case, the sources said, adding the probe was still on.
The militants, according to the sources, had arrived in Bangladesh from Pakistan.
Jaish-e-Mohammed is headed by Masood Azhar, who was released in 1999 in exchange of hijacked passengers of IC-814.
He had mentioned about the plan to attack the Ram temple in his diary when he was arrested in mid-90s, the sources said.
Of the five militants killed in Ayodhya, one had visited Darul-ul-Uloom Deoband and is also alleged to have stayed there for sometime before moving to Faizabad for carrying out the attack.
Militants belonging to Jaish-e-Mohammed are followers Deoband sect whereas Lashker cadres are supposed to be followers of Al-Hadees or Wahabi sect of Muslims.
The Deoband sect is more familiar in Bangladesh and its militant outfit in that country is Harkar-ul-Jehadi Islamia, which has been spreading terror and anti-India sentiments.
The officer also said the recent bomb blasts in Dhaka were a matter of 'serious concern for us'.