Suspect charged with murder in May Jewish Museum shooting which killed 4

File - In this Thursday, June 12, 2014 file of an artists sketch, depicting Mehdi Nemmouche, right, as he stands next to a police agent during his court appearance at Versailles Court of Appeal. On Tuesday, July 29, 2014, France extradited Nemmouche suspected in the shooting dead of four people at the Jewish Museum in Brussels, to Belgium. (AP Photo/Benoit P., File) (The Associated Press)

Sebastien Courtoy, right, and Henri Laquay, the two lawyers of suspect Mehdi Nemmouche, walk in front of the press at the headquarters of the federal police in Brussels on Tuesday, July 29, 2014. France on Tuesday extradited Mehdi Nemmouche, 29, who is suspected of shooting dead four people at the Jewish Museum in Brussels. (AP Photo/Thierry Monasse) (The Associated Press)

The man suspected of killing four people at the Brussels Jewish Museum in May has been charged with "murder in a terrorist context."

One day after his extradition from France, federal police said Wednesday that Mehdi Nemmouche had also been interrogated by a counter-terrorist unit.

Nemmouche agreed to his extradition only after he received sufficient guarantees he would not be turned over to a third country. Nemmouche, 29, had fought with Islamic extremists in Syria.

On May 24, a lone gunman walked into the Jewish Museum in the center of Brussels, unpacked a Kalashnikov rifle, killed four people with a burst of fire, packed up and walked away.

Nemmouche was arrested at a Marseille bus station a few days later carrying weapons resembling those used in the killings.