He Was Accused of Sowing Terror Overseas. He Was Caught by the N.Y.P.D.

The next day, a female detective who testified as Undercover 487, took over the role of Rojin from Mr. Aykac. She appeased Ms. Kokayi on a video call that was shown to the jury. Then, prosecutors said, she met with Mr. Kokayi in New York and Washington.

In late 2016, Undercover 487 told Mr. Faisal that she was in Jordan, according to records of a Skype call entered into evidence. Less than an hour later, evidence shows, Mr. Faisal texted her the phone number of an ISIS fighter in Raqqa, Syria.

The evidence also shows that Mr. Faisal agreed that someone whom Undercover 487 described as a “Pakistani sister” named Mavish could contact him.

So the New York Police Department deployed a third detective, a woman in her 20s who was born in Pakistan and testified as Undercover 716. She posed as a former medical student from New York who was working as a “patient transporter” in a hospital and could help treat injured ISIS fighters. In late 2016, evidence shows, she told Mr. Faisal by text message that she planned to “leave work for good,” adding that it was “for hijrah.”

“We will plan together,” Mr. Faisal wrote back, the records show, and the two communicated for weeks, with Mavish saying she wanted a husband who shared the “same beliefs.” Mr. Faisal first tried to convince Mavish to marry him, then asked if she would be willing to marry a Somali man in Canada or a Pakistani man in Britain.

Mr. Faisal had been apprehensive about communicating with someone in the United States, believing those exchanges could be monitored, Undercover 716 testified. So in early 2017, the New York detective flew to Abu Dhabi.

She sent him a selfie in front of the Sheikh Zayed Grand Mosque there, telling him she needed to find a way into ISIS territory. The department’s investigation then extended further: Mr. Faisal sent her a phone number for a fighter in Syria named Luqmaan Patel, records show.