As part of a probe into his killings, France's DCRI domestic intelligence agency has released documents relating to the Al-Qaeda-inspired Islamist who killed seven people in March.
French intelligence has been criticised since it emerged that it was known Merah had travelled to Pakistan and Afghanistan before he went on his killing
Both Merah and his older brother Abdelkader had been under surveillance by the DCRI since 2009, according to the documents, in particular after the two travelled in 2010 to Egypt, where Merah went to learn Arabic.
Identified in 2010 as a "new recruit" in radical Islamist circles in Toulouse, Merah was questioned by the DCRI late last year after a trip to Pakistan.
In a document written in December, the service warned of Merah's "worrying behaviour" and said he was a "privileged target" for further surveillance.
Merah shot dead three Jewish schoolchildren, a rabbi and three paratroopers before being killed himself on March 22 following a 32-hour police siege of his flat in the southern city of Toulouse.
Lawyers for families of the victims have said the documents declassified so far are insufficient to know the truth and are calling for DGSE foreign spy agency files to also be released.