Xavier Raufer, a former high-level police officer and expert on terrorism, told The Anadolu Agency on Thursday that two of the suspects had been known to police for years.
"This is a family group, not an international terrorist organization," Raufer said. "Despite the careful military planning, the attacks were carried out by a radicalized family group."
Raufer said that Cherif Kouachi, who was jailed in 2008 for participating in a group inciting young people to fight in Iraq, became radicalised in prison.
He communicated his beliefs to his brother, Said Kouachi, and to the third suspect, Hamyd Mourad, a friend.
"At no time since his incarceration did Kouachi have any contact with extremist groups in France or abroad," Raufer said. "What happened is that the police ceased paying attention to Kouachi's activities, as they were prioritizing surveillance on those who had fought in Iraq or Syria, or those who expressed an interest in doing so. This choice has had unfortunate consequences."