A Columbia University-educated doctor who was taped swearing loyalty to Al Qaeda was found guilty by a jury yesterday of conspiring to provide material support to a terrorist organization.

The doctor, Rafiq Sabir, 52, was the only one to stand trial among four men arrested in a wide-ranging terrorism sting operation. The other three all pleaded guilty to a range of charges. Sabir faces up to 30 years in prison.

The prosecution’s case against Sabir, of Boca Raton, Fla., was based on a meeting he attended in a Bronx apartment in 2005 at which an agent with the Federal Bureau of Investigation was posing as a recruiter for Al Qaeda.

At the time, Sabir had a contract with a hospital in Saudi Arabia. At the meeting, the undercover agent told Sabir that he would be a valuable asset for Al Qaeda if he could move around that country giving medical aid to mujahedeen who are hurt, according to a recording played at trial. Sabir ended the meeting by pledging an oath of loyalty to Al Qaeda in Arabic, according to the tape.

Sabir testified that, due to his limited Arabic, he did not know to whom he was swearing the oath according to news reports of his testimony.

Sabir’s lawyer, Edward Wilford, told Reuters that the verdict “is another example of the erosion of constitutional rights that we suffer post-9/11.”

Before the trial, Mr. Wilford had unsuccessfully challenged the legality of the charges against his client, claiming that Sabir’s ethical responsibility as a doctor precluded him from not treating the wounded, even if they were jihadists.

A friend of Sabir who was also present at the meeting, a martial arts instructor named Tarik Shah, was taped giving a similar oath. Shah pleaded guilty and has not been sentenced.