The assailant escaped the scene of the crime on a motorbike, but was later arrested by the Carabinieri, Italy’s national military police, in the city of Vimercate, located some 25 kilometers from Milan, the country’s Interior Minister Angelino Alfano said.
The reports added that the gunman was at the courthouse on Thursday for a bankruptcy case.
Giovanni Canzio, the president of Milan’s appeals court, identified the slain judge and attorney as Fernando Ciampi and Lorenzo Alberto Claris Appiani.
Two people were also injured in the shootout and one is in a serious condition.
Valerio Maraniello, who once acted as a lawyer for the shooter, described his former client as “an aggressive person, a little paranoid.”
“He was always convinced people were trying to cheat him. He never listened to advice,” he said, adding that he was “not completely surprised” by the deadly shooting.
The incident raised concerns over the efficiency of the security measures in the courthouse, which is protected by metal detectors at its four main entrances.
“It’s disturbing that just anyone can get into the Palace of Justice armed,” said the head of the Lombardy region, Roberto Maroni, adding, “The fact that we’re not talking about an organization which surveyed the place first makes it even more perturbing.”
The Palace of Justice is situated in the historic center of Milan, only a few streets away from the city’s cathedral and shopping district.