Abdelkader Merah, the elder brother of the slain shooter who has been in detention after his March arrest, accompanied the police officers during the operation, police officials said.

The raid on the single-storey house in Auterive south of Toulouse is aimed at finding "complementary" evidence, police said.

The elder Merah who has been indicted, is due to appear before an anti-terrorism judge on September 10th. Investigators are trying to establish if he influenced his brother's conversion to hardline Islam.

Abdelkader Merah has said he and another individual were present when his brother bought a jacket which he wore while staging his deadly shootings in Toulouse and Montauban. But he has refused to reveal the identity of the other person.

The 29-year-old also said the same individual was present when a scooter was stolen that his brother used to stage the attacks.

Abdelkader Merah is suspected of involvement in the preparating for the murders and the killings themselves.

Meanwhile, Bernard Squarcini, the former head of domestic intelligence agency DCRI, told AFP Wednesday he had been heard "this week" by the examining magistrate about the way the agency handled the case.

The move follows a call by the families of the victims after the release of DCRI documents which suggest the killer should have been under much closer surveillance than he was.

They said Mohamed Merah had made nearly 2,000 telephone calls between September 2010 and February 2011, one in 10 of them to people located in a total of 20 foreign countries.

During the time that his calls were being monitored, Merah called or texted numbers in Egypt at least 94 times. Other calls were made to Britain, Spain, Ivory Coast, Kenya, Croatia and Bhutan.

It had previously emerged that Merah was under surveillance from the end of 2009 and that his behaviour was classed as "worrying" in late 2011 following his return from a trip to Pakistan.

Four months after that report, Merah shot dead a rabbi named Jonathan Sandler, his two children and one of their schoolmates as well as three French paratroopers.

Merah was killed himself on March 22nd following a 32-hour police siege of his flat in Toulouse.