The case was later shifted to Detective Branch of police for investigation.
A case was filed here on Tuesday over the killing of an accused by another accused in a courtroom during a hearing on Monday.
Assistant sub-inspector Firoz of Bangara Police Station, who was present at the court during the incident in connection with another case, filed the case with Kotwali Model Police Station against lone accused Hasan in the morning, said Inspector (Investigation) of the police station Mohammad Salauddin.
The case was later shifted to Detective Branch of police for investigation, he said.
Meanwhile, DB Inspector Pradip Mondal has been appointed investigation officer of the case.
Hasan, a murder case accused, stabbed another accused Faruk, son of Ohid Ullah of Monaharganj in the district, to death in front of the Judge in a courtroom here during the hearing on Monday.
The shocking incident took place in front of Judge Begum Fatema Ferdous of Cumilla Sessions Judge (third) court in the courtroom.
The deceased and the attacker happen to be cousins.
Cumilla Police Super Syed Nurul Islam said accused Hasan started stabbing Faruk with a knife indiscriminately while the hearing in the murder case was going on in the court around noon, leaving him critically injured.
Faruk was taken to Cumilla Medical College Hospital where doctors declared him dead.