(AP) Two brothers are suddenly the most wanted men in France, suspected of the armed onslaught on a newspaper office that claimed a dozen lives and horrified most of the world.

Cherif Kouachi, 32, and Said Kouachi, 34, were the targets of a mammoth manhunt following Wednesday's slayings at the Paris offices of the satirical weekly Charlie Hebdo.

The younger Kouachi, a former pizza deliveryman, had been sentenced to 18 months of prison in 2008 after trying to leave France to join Muslim fighters battling in Iraq.

Associated Press reporters who covered the trial, which exposed a recruiting pipeline for Islamic holy war in a rough multiethnic and working-class neighborhood of northeastern Paris, recalled a skinny young defendant who appeared very nervous in court.

Cherif Kouachi's lawyer said at the time his client had gotten in over his head with the wrong crowd.

During the trial, Kouachi was said to have undergone only minimal training for combat, going jogging in a Paris park to shape up and learning how a Kalashnikov automatic rifle works by studying a sketch. He was described at the time as a reluctant holy warrior, relieved to have been stopped by French counterespionage officials from taking a Syria-bound flight that was ultimately supposed to lead him into the battlefields of Iraq.

But imprisonment changed his former client, attorney Vincent Ollivier told Le Parisien newspaper in a story published Thursday. Cherif Kouachi became closed off and unresponsive and started growing a beard, the lawyer said, adding the time in prison may have turned his client into a ticking time bomb.

However, a French television documentary that portrayed Kouachi's abortive attempt to fight in Iraq suggested his radicalization may have occurred well before he was locked up behind bars. Many French Muslims were infuriated by the 2003 U.S. invasion and occupation of Iraq, the program said, and by the negative consequences for Iraqis, ranging from the death of civilians to the abuse of detainees by American captors.

Footage included in the 2005 documentary, part of a prestigious French public television series entitled "Evidence for the Prosecution," showed Kouachi in 2004, when, according to the narrator, the young man in a black T-shirt with extremely close-cropped hair and a chunky wristwatch was more interested in pretty girls than going to the mosque. He appears relaxed and smiling as he pals around with friends.

At one point, with a baseball cap turned backward on his head, Kouachi belts out some rap music and breaks into a joyful dance.

It was the teachings of a radical Muslim preacher in his Paris neighborhood, Kouachi is quoted as saying in the documentary, that put him on the path to jihad.

The cleric "told me that (holy) texts prove the benefits of suicide attacks," Kouachi is quoted as saying. "It's written in the texts that it's good to die as a martyr."

Less is known publicly about Said Kouachi, the older brother, but French Prime Minister Manuel Valls told French radio Thursday that both were known to intelligence services and were likely being followed before the Charlie Hebdo attack.

A third suspect identified by French authorities in the Paris newspaper attack that killed 12 people and wounded 11 others has turned himself in. Mourad Hamyd, 18, surrendered at a police station after learning his name was linked to the attacks in the news, Paris prosecutor spokeswoman Agnes Thibault-Lecuivre said, but she did not specify his relationship to the Kouachi brothers.