During a day of interrogation, Durn told police he often "thought about killing someone and killing himself afterward".
Durn sat quietly through six hours of debate about the Nanterre budget before opening fire on council members.
Prior to joining ATIC, Durn
was an investment banker and a member of the Merger Leadership Group at Goldman Sachs.
To his mother, Durn
wrote: "Mama, I should die at least with the feeling of being free and getting a kick out of it.
Police said in a statement that Durn was being quizzed in an attic office when he suddenly leapt for the skylight.
15am, two officers from the Criminal Brigade were continuing the questioning of Richard Durn, which had begun the day before.
Durn was arrested after wounding councillors who managed to overpower him.
Durn is a gun club member and hardline green activist with a history of mental illness.
, 33, a known suicide risk, was being questioned by detectives yesterday when he threw himself through an attic window of an interrogation room in the heart of Paris.
, an ecology and Third World activist, sat through a six hour council meeting at Nanterre in north west Paris before calmly opening fire at 1.
continued to visit a club for target practice.
His mother Stephanie Durn
later said: "The reason why I think he wanted to kill was because he felt very alone", adding that he had spoken of wanting to kill "many times .