A top police official had alerted security officials in an advisory 10 days ago about a threat to churches from a radical Islamist group, National Thowheeth Jama’ath, New York Times reported.

The top Sri Lankan police official had issued a letter on April 11 to government security officials warning of possible suicide attacks planned at Catholic churches.

This advisory sent by a police official alerted security officials about a threat to churches from a radical group, National Thowheeth Jama’ath.

The document, provided by a government official, could not be independently verified, and it is unclear if the group played a role in the violence.

“You should instruct all personnel to pay strict heed to this report and be extra vigilant and cautious of the V.I.P.s and locations coming under your purview,” wrote Priyalal Dassanayake, the deputy inspector general said in the advisory.

The letter, citing foreign intelligence officials, identified the group suspected of planning attacks as National Thowheeth Jama’ath.

“Highly confidential investigations regarding the above are in process,” the letter said.

Still, it remained unclear Sunday what steps the authorities had taken to try to forestall an attack.

“We must look into why adequate precautions were not taken,” said Prime Minister Wickremesinghe. Neither I nor the Ministers were kept informed.”

A string of eight devastating blasts, including suicide attacks, struck churches and luxury hotels frequented by foreigners in Sri Lanka on Easter Sunday, killed 215 people in the island nation.

The bombings began around 8:45 a.m., and targeted Roman Catholic houses of worship — St. Anthony’s Shrine in Colombo, the capital; St. Sebastian’s Church in Negombo; and Zion Church in Batticaloa — along with three luxury hotels: the Shangri-La, the Cinnamon Grand, and the Kingsbury, all in Colombo.

Thirteen suspects were held in connection with the bombings, the authorities said. Three officers were killed hunting for the attackers at a housing complex.