Two convicts in Holey Artisan attack case wore the caps when sentenced to death for the 2016 attack
He made the claim when produced at Dhaka Anti-Terrorism Special Tribunal on Tuesday, for a hearing in a case filed over Kalyanpur militant raid in 2016.
During the hearing, when Judge Md Majibur Rahman asked Regan from where he got the cap, he answered someone passed it to him from the crowd.
Regan, however, did not mention anything about the place he collected it from.
When the judge asked him the reason for wearing the cap, Regan replied:"As the cap was inscribed with Arabic letters, I felt good and wore it."
Earlier in the day, seven accused, including Regan and five other death row convicts in Holey Artisan attack case, were produced before the court.
On November 27, the same court sentenced seven people to death in the Holey Artisan attack case.
Soon after the verdict was given, Regan wore the Islamic State-emblazoned cap.
Regan still had the cap on when police brought him out of the courtroom and took him to a prison van.
Inside the van, another death row convict named Jahangir Alam alias Rajib Gandhi, was seen wearing a similar cap.
After the incident, a prison authority probe found that the caps worn by the two convicts were not supplied from jail.
Earlier, Additional Inspector General of Prisons Colonel Md Abrar Hossain, told the Dhaka Tribune: "They were actually supplied by an unknown civilian inside the courtroom."
On the other hand, after a primary investigation, Dhaka Metropolitan Police (DMP) Detective Branch (DB) Joint Commissioner Mahbub Alam said those infamous caps were most likely brought by the convicts from prison.