Milan, April 9 (IANS/AKI): A bankruptcy judge was among four people killed at Milan's main courthouse on Thursday, when a gunman opened fire inside the building.

Several people were injured in the attack, after which the gunman fled before being arrested by police.

Fernando Ciampi was killed when the gunman, identified as fraudulent bankruptcy defendant Claudio Giardiello, fired four or five shots at him and at several witnesses at the trial in Italy's northern business capital.

Besides Ciampi, a lawyer named Lorenzo Alberto Claris Appiani and a third unnamed victim died in the attack, emergency services said.

Another defendant at the trial who was wounded in the attack reportedly died later in hospital, while a witness was critically injured and two people suffered a cardiac arrest.

Police evacuated hundreds of people from the courthouse building after the attack and Giardiello managed to escape on a motorbike. He was arrested by police in the town of Vimercate, 25 km from Milan, Italy's Interior Minister Angelino Alfano said in a message on Twitter.

Giardiello, 57, is an Italian facing bankruptcy charges. Dressed in a jacket and tie, he reportedly opened fire after Appiani, his lawyer, said he could no longer represent him in the case.

"It is disturbing and incomprehensible how anyone could enter the courthouse with a gun," said Roberto Maroni, governor of the surrounding Lombardy region, commenting on the attack.

"We express our profound dismay and pain at the tragic events at Milan's courthouse," said the Italian magistrates association in a tweet.