The head of the French intelligence agency DCRI said in an interview on Friday that the Toulouse shooter was arrested by Israel Police in Jerusalem in 2010, after he was found in possession of a knife.

Bernard Squarcini told the French newspaper Le Monde that Mohamed Merah, who killed four people in an attack on a Jewish school in Toulouse on Monday, was held by police in Jerusalem during his visit to Israel in 2010, but was released shortly after his detainment.

Squarcini said that Merah visited several other Middle Eastern countries during that trip, including Turkey, Syria, Lebanon, Jordan, and Afghanistan. He said that French intelligence tracked him and investigated to see if he is suspicious, but found that he had not been engaging in any ideological activism or religious activity.

Squarcini responded to allegations about the French intelligence services' failures during the hunt after Merah.

When asked about French Interior Minister Claude Guean's statements about a possible intelligence failure, Squarcini said that the minister's words were misinterpreted. "People, including children, died in a cruel way," he said, "and we inevitably ask the question - could we have done something different? Did we miss something? Were we fast enough?"

On Thursday, Le Monde reported that Merah was not a member of any well-known Islamic terrorist organization, but did undergo a process of radicalization. He was also added to a "no fly" list maintained by U.S. authorities some time ago, two American officials told Reuters. The officials would not disclose precisely when Merah was placed on the list.

Meanwhile, a little-known extremist group on Thursday claimed responsibility for a series of deadly shootings in France, saying they were in response to what it called "Israel's crimes" against the Palestinians.