The pistol that was found inside the private car hit by a train at Malibagh level crossing on Friday belonged to Narayanganj seven-murder prime accused Nur Hossain.
Abdul Majid, officer-in-charge of Dhaka Railway Police Station, said the Austrian made pistol was licensed in Nur's name.
Three passengers of a private car were injured as a train heading for Kamalapur railway station hit the car while crossing the level crossing.
Police found the pistol along with 20 rounds of bullets, several number plates of cars and new clothes inside the damaged car, said Sub-Inspector Imam Arefin of Dhaka Railway Police Station. The weapon was loaded with 12 of the bullets, he added.
Nur Hossain and his family members had 11 licensed weapons. Police seized nine of the weapons after the seven murders on 27 April, said Mohammad Allauddin, officer-in-charge of Shiddhirganj Police Station.
Documents of the recovered weapon showed that it was issued in the name of Nur Hossain, he added.
Police suspected that the passengers of the car were relatives of Nur, who is now in Indian jail.