Rab sources said the four set out for Comilla from Dhaka to track down Khaled Saifullah, absconding Majlish-e-Shura member of the outlawed Jama'atul Mujahideen Bangladesh (JMB).

They reached Comilla town in the evening and located an area where Saifullah might be hiding. They called for reinforcement to cordon off a 1-by-1.5-kilometre area surrounding Kaliajuri, Bishnupur and Judge's Court.

Sources said Rab was working from March 7 to track down Saifullah, who was acting as JMB in-charge of Rangpur-Dinajpur region.

"Some Rab officials from Rab-5 [Rajshahi] came to Dhaka after getting tentative location of him in Dhaka," a Rab officer told The Daily Star.

They searched for Saifullah during March 7-9 in Dhaka through different sources to learn that he escaped to Comilla.

The Rab officials visited Comilla several times and tried to collect information about his whereabouts. "We tried to locate him in the last three days," said an officer who took part in the operation.

After receiving Saifullah's confirmed location, the four Rab officers from Rab-5 and the headquarters -- deputy directors Major Faruq and Major Joha and assistant directors Captain Sharif and Flight Lieutenant Mostafa -- started for Comilla.

Saifullah was on the run and was staying at Kazi Rowshan Villa until the early hours of March 12, admitted Khaleda Akhter Rani, wife of Salam who was reportedly accompanying the JMB leader.

Rab arrested Rani and seized huge explosives including three live bombs and hand grenades from the house. She told the Rab the two had started for Dhaka.

The Rab men however said they are not confirmed yet whether Saifullah left the house sensing the operation.

Rab Intelligence Wing Director Lt Col Gulzar Uddin Ahmed told reporters in Comilla that they got clues to a JMB hideout in Comilla town. He added that JMB chief Abdur Rahman also told interrogators Saifullah and Shakil alias Mollah Omar were staying there.

"Following that information, Major Joha and Major Faruk came here and conducted a raid on the Bishnupur house after pinpointing their hideout at 3:00am," said Gulzar.