New details are emerging about the agent sent by Saudi counterterrorism agents into Yemen to track a plot by al Qaeda in the Arabian Peninsula to bomb a U.S.-bound airliner.

The agent is of Arabic origin but holds a British passport, according to Mustafa Alani, director of security studies at the Gulf Research Center. Alani was briefed on the operation by Saudi counterterrorism officials.

The agent, whom another source said had Saudi roots, lived for a long time in the UK and at some point fell in with jihadist sympathizers, Alani told CNN. That made him an attractive target for Saudi counterterrorism agencies, which recruited him about a year ago, Alani said.

His background gave him the credibility to infiltrate AQAP, the Yemeni-based branch of the terrorist organization, which is exceptionally careful about whom it accepts and trusts. At the same time, his possession of a British passport enhanced his appeal to the terror group — because he could travel without a visa to the United States.

According to Alani, the agent was sent into Yemen as a potential suicide bomber after the Saudis heard from other informants that a new AQAP plot was in the works. The agent enrolled in an Arabic language school in Yemen in the hope of being talent-spotted by the group.

AQAP fell for the bait and the mole connected with the group. After he joined them he had to handle the tremendous pressure of what discovery by al Qaeda would entail, said Alani.

Two or three months ago, the agent learned that the group was working on a new device to bomb a U.S.-bound airplane, and he contacted Saudi counterterrorism officials from Yemen. At this point they informed the Americans of the potential threat, and that they had a mole inside the group, according to Alani.

The agent was later provided training in how to use the explosive device in a training facility in Yemen, possibly inside a safe house, according to Alani.

READ MORE: CNN