Mohammed Merah, a 23-year-old man described by French authorities as a self-styled al Qaeda jihadist, has been named as the chief suspect in a series of shootings that have left seven people dead.

A picture is emerging of a man who was already known to the police and had apparently sought out Islamist jihadists in Pakistan and Afghanistan.

"He claims to be a jihadist and says he belongs to al Qaeda," Interior Minister Claude Gueant told reporters in Toulouse. "He wanted to avenge the Palestinian children and take revenge on the French army because of its foreign interventions."

A French national of Algerian origin, he had been under surveillance by French intelligence for a couple of years, having "already committed certain infractions, some with violence," Gueant told CNN affiliate BFM-TV.

Merah has spent considerable time in Afghanistan and Pakistan, Gueant said. Merah was sent back from Afghanistan to France by the U.S. Army, Paris prosecutor Francois Molins said in Toulouse Wednesday. He said Afghan police had checked Merah's identification during a traffic stop, and as a result he was handed over to the U.S. Army, which then put him on board the first plane heading to France.

But a senior U.S. military official gave a different version from the French prosecutor about what happened to the suspect in Afghanistan.

The senior U.S. military official told the CNN contributor Fran Townsend that the French shooting suspect was stopped by Afghan forces who tried to turn him over to the U.S. military. The U.S. directed them to hand Merah to French forces since he was a citizen of their country. He was given over the French military by the Afghans and the French military decided to return him to France, according to the source.