Vinas' name appears on a list of potential witnesses in the case against Adis Medunjanin - and officials say he would offer a unique perspective on the inner workings of the terrorist group and how it indoctrinates born-in-the-USA extremists.
Medunjanin has pleaded not guilty in federal court in Brooklyn to charges accusing him of traveling to Pakistan with two former high school classmates, Najibullah Zazi and Zarein Ahmedzay, to seek terror training there and hatch their scheme back home.
Zazi, a former Denver airport shuttle driver, and Ahmedzay admitted in guilty pleas that they wanted to avenge U.S. aggression in the Arab world by becoming martyrs in a suicide attack on Manhattan subway lines in 2009. Both are key witnesses against Medunjanin.
Vinas, 29, was never charged in the case. But he is an intriguing and valuable cooperator because he had extraordinary access to al-Qaeda's leadership, a U.S. official said.
Known by the nicknames "Ibrahim" or "Bashir al-Ameriki," Vinas met on a few occasions with Abu Yahya al-Libi, al-Qaeda's now No.2. He also mixed with Mustafa Abu al-Yazid, the top commander in Afghanistan and Atiyah Abd al-Rahman, who orchestrated a plot involving a double agent that led to the killing of seven CIA employees - both since killed in drone strikes.
A video released in October 2008 and shot at an al-Qaeda outpost shows al-Libi with an armed man believed to be Vinas - his head wrapped in a scarf and an ammo belt around his waist - a month before his capture, said the official, speaking on condition of anonymity because the case is ongoing.
Vinas also could captivate the jury with his personal tale of radicalization - a subject of intense interest to counterterrorism officials concerned about homegrown threats. He also could explain what convinced him to betray al-Qaeda.
"He's a fascinating story," said Steve Zissou, Vinas' lawyer, declining to confirm if his client will testify.
The story began in Medford, N.Y., a suburban community on Long Island where Vinas grew up the son of a Peruvian immigrant. His childhood seemed unremarkable: Family and friends said he went to a Catholic church, blended in at the local high school and had a passion for baseball.
At some point, Vinas took the name Ibrahim and began attending services at the Islamic Association of Long Island, a mainstream mosque in nearby Selden. The president of the mosque recalled him as "very quiet, polite, smiley" - a calm disposition that apparently masked a growing resentment toward his own country.
By his own admission, Vinas traveled to the dangerous tribal lands of northwest Pakistan, intent on fighting against U.S. forces in Afghanistan. Unlike other aspiring terrorists who didn't survive the al-Qaeda vetting process, Vinas apparently was embraced.
Vinas told a judge he swore loyalty to the terrorist group and underwent weapons and explosives training. In September 2008, he took part in a failed attack using rockets on a U.S. base in Afghanistan.
Bashir al-Ameriki had at least two other assets that made him valuable as a fledgling al-Qaeda operative: A U.S. passport that could let him slip back into the United States undetected and a firsthand knowledge of mass transit.
No sentencing date has been set.