Abdelhamid Abaaoud syria
Abdelhamid Abaaoud was the mastermind behind the Paris attacks Reuters

Abdelhamid Abaaoud's younger brother Yassine has reportedly been under arrest in Morocco for the past month, security sources in the north African kingdom have revealed. Yassine Abaaoud was picked up by Moroccan authorities when he arrived by plane in his father's home town of Agadir, Reuters reported.

An unnamed security source told the news agency he was unable to give further details about the arrest. It was not immediately clear whether Yassine had ties to his brother's terror cell.

Abdelhamid Abaaoud was killed in a police raid in the Paris suburb of Saint-Denis on 18 November with two others. The leader of the Islamic State (Isis) cell behind the Paris attacks, in which 130 people were murdered, has also been held responsible for a string of attempted terror attacks across Europe in recent months.

Another brother of Abdelhamid Abaaoud made news in August when 13-year-old Younes Abaaoud became one of the youngest people to travel to Syria to join IS. Younes, from Belgium, followed his older brother to the front line and is understood to be among dozens of child fighters from Europe in the war zone.

The Morocco link

On 16 November, four agents of the Moroccan secret services met leaders of the French police, France Info reported. On 19 November, French interior minister Bernard Cazeneuve revealed the whereabouts of the suspected Paris commando had been tipped off by a "country outside Europe", Morocco.

Sources close to the Moroccan intelligence claim the agents offered this advice: "Follow the cousin of (the Paris attacks) mastermind Abdelhamid Abaaoud: her name is Hasna Aitboulhacen. She lives in France. She is ultra-radicalised. Follow his trail... Listen to her! "

The young woman, who held French-Moroccan citizenship, was already tapped in France, in a drug-trafficking case. But following Morocco's guidance, French anti-terrorist police started tapping Aitboulhacen on a "judiciary basis" after it was believed she was constantly in touch with Abaaoud.

iTele reported that investigators traced the terrorists to Aitboulahcen's flat after tapping her conversations - the scene of the raid in Saint-Denis, Paris. She detonated a suicide vest during the raid by French police and soldiers..

UPDATE

2:34pm GMT: Reuters reports that French police on Tuesday (17 November) followed "a woman" they knew had links to Abdelhamid Abaaoud, the suspected mastermind of the attacks and watched her take him into the building that special forces attacked early the next morning.

"A physical surveillance took place which allowed us to establish that the young woman and the jihadist went into the building in Rue Corbillon in Saint-Denis on Tuesday early in the evening," said the police source, declining to be identified because he is not authorised to speak officially.

French police had been tapping the phone of Hasna Aitboulahcen as part of an investigation into potential drug offences and were able to track her down in the Saint-Denis suburb north of the French capital.