A Brussels school attended by Bilal Hadfi, the youngest of the nine terrorists that attacked Paris, has said authorities ignored its warning about his radicalisation. The Annessens-Funck school said Hadfi had recently turned to radical Islam and jihad, and may have travelled to Syria in February.

Hadfi, 20, blew himself up outside the national soccer stadium in northern Paris after the attacks. The orchestrated attacks across Paris claimed 130 lives.

Hadfi's teachers had become concerned about his increasingly radical views, especially his comments over the January attack on the French satirical magazine Charlie Hebdo. Teachers say he hailed the Charlie Hebdo attack, saying the Frenchmen had failed to recognise warnings about disrespecting Islam.

In the middle of February, Hadfi stopped showing up to school and rumours started to float that he may have left for Syria to fight for the Islamic State (Isis). Pictures taken from Bilal's Facebook page show he had changed his name to Abu Moudjahid al-Belgik. One showed him posing in front of an IS flag.

When the school's director, Chris Pijpen, visited Hadfi's parents to discuss the issue he was told the boy had gone to Morocco. Suspicious about the facts, he decided to report the matter to authorities, as required by Belgian law.

In an email in April, Pijpen reportedly informed his senior education official, Charles Huygens, about Hadfi. However, Huygens never took forward the warning, the school said.

Huygens acknowledged receiving the email but told Flemish newspaper De Morgan the warning came too late. "It's true the director reported to me about this in April but by then it was too late. He left for Syria and there was nothing we could do," Huygens said. Now a police oversight body known as Committee P is investigating why the warning was not passed on to the authorities in time.

Authorities are also questioning school staff for further details on Hadfi. Police are trying to establish any links Hadfi may have had with another Paris attacker, Brussels-born Salah Abdeslam, who is reportedly hiding in or around Belgium.

Days after the Paris attacks, after Hadfi's involvement was known, Huygens suspended Pijpen for coming late to a meeting. A spokesman for the teachers union, Frank Van de Vyver, told New York Times, "Pijpen was suspended for a reason other than being late to a meeting. The school was looking for a scapegoat that would divert attention from the fact that they did nothing with the very sensitive information they got."