(CNN) — French intelligence services believe Paris attacks suspect Salah Abdeslam has escaped to Syria, according to a source close to the investigation and a counterterrorism source.

Investigators have been looking for Abdeslam since shortly after the November 13 attacks, which killed 130 people.

The possibility that Abdeslam had already slipped through authorities’ net was raised last week when a lawyer said his client, Ali Oulkadi, picked up Abdeslam and a friend at a subway stop in suburban Brussels the day after the attacks.

“He did not know it was Salah and did not recognize him immediately when he arrived because he was wearing a cap,” lawyer Olivier Martins said. “In the car, Salah told him that his brother, Brahim, had killed people in Paris and had blown himself up. For my client, a childhood friend of the two brothers, it was a shock, He could not understand it and could not think clearly.”

On the way back to the Brussels neighborhood of Schaerbeek, the trio stopped in a cafe, the lawyer said.

Investigators haven’t detailed what they believe Abdeslam’s role was in the coordinated series of attacks, but Paris Prosecutor Francois Molins said he may have dropped off suicide bombers at the Stade de France and then made his way to another Paris neighborhood. His fingerprints, Molins said, were found in a car connected with the attacks.

On the night of the attacks, authorities say, two men from Belgium drove to Paris to pick Abdeslam up and take him back to Brussels.

Abdeslam allegedly had called the men — identified as Mohammed Amri, 27, and Hamza Attou, 21 — to say that his car had broken down.

Oulkadi’s alleged encounter with Abdeslam, according to Oulkadi’s lawyer, happened on the afternoon of November 14 — shortly after Amri and Attou are said to have driven Abdeslam back to Brussels.

Oulkadi, Amri and Attou are among six people that authorities in Belgium — whose capital city is said to be a hotbed of European jihadism — are holding in connection with investigations into the Paris attacks.

Amri and Attou were arrested in Belgium on November 14 and have been charged with terrorism offenses. Lawyers for the two men say they had no idea of Abdeslam’s alleged involvement.

A court on Friday ordered Oulkadi, identified by Belgium’s federal prosecutor only as Ali O., detained for a further 30 days.
Martins said Oulkadi had done nothing wrong.

“He was in Brussels during the evening of Friday, November 13th, has no criminal record and is absolutely not radicalized,” Martins said. “When he learned that Salah was wanted, he should have gone to the police and told his story, but he was scared and didn’t get the right advice at the time.”

The-CNN-Wire ™ & © 2015 Cable News Network, Inc., a Time Warner Company. All rights reserved. (PHOTO: CNN)