Opening statements began Wednesday in the Manhattan trial of Sulaiman Abu Ghaith, the son-in-law of Osama bin Laden and a high-ranking al-Qaeda member who was captured last year after he left Iran, where he had been held for more than a decade.

Assistant U.S. Attorney Nicholas Lewin told an anonymous jury that Abu Ghaith, a Muslim cleric from Kuwait, had played a critical role in the terrorist group before and after the attacks of Sept. 11, 2001.

Lewin said Abu Ghaith had a “twisted view of Islam” and used the “murderous power of his words” to inspire hundreds of recruits and attract others from around the Persian Gulf region. His job was to “provide the al-Qaeda with its very lifeblood — fighters,” the federal prosecutor said.

The balding Abu Ghaith, in a blue suit and tie and his graying beard neatly trimmed, listened impassively through a courtroom interpreter. The 48-year-old faces several terrorism charges, including conspiracy to kill Americans and providing material support to terrorists. If convicted, he faces life in prison.

Prosecutors said that although Abu Ghaith did not plan al-Qaeda’s attacks, bin Laden relied on him heavily in the weeks and months after the Sept. 11 attacks and that he produced propaganda videos at the request of the al-Qaeda leader. One of the videos depicted Abu Ghaith warning that the “storms shall not stop, especially the airplane storms.” He warned Muslims “not to board any aircraft and not to live in high rises.”

Stanley Cohen, Abu Ghaith’s attorney, said the government has no real evidence against his client, only “words and associations.” He said the trial, taking place 10 blocks from where two hijacked planes brought down the World Trade Center, is about fear mongering. He said that “9/11 hangs heavy over this courtroom.”

Cohen said there will be a “substitution of evidence with fright” and attacked the government’s case, which he said rested almost entirely on two unreliable witnesses and the videos.

Cohen said his client was a “talker” and an “ideologue” who said some dumb things but is not guilty of the crimes with which he has been charged. The lawyer compared Abu Ghaith to Capt. Thomas Preston, a British soldier acquitted of ordering the 1770 Boston Massacre. Cohen conceded that he was no John Adams, who defended Preston and later became president. The lawyer’s comment elicited a few chuckles in the courtroom.

Members of Congress are expected to closely watch the trial because of the continuing debate about whether civilian courts or military commissions are the proper venue to try terrorism suspects captured overseas. Critics of federal criminal trials recall the case of Ahmed Khalfan Ghailani, who was acquitted in 2010 of all but one of 280 charges in the same courthouse where Abu Ghaith is on trial.

Ghailani was convicted of conspiring to damage or destroy U.S. property but was acquitted of multiple murder and attempted murder charges in the 1998 U.S. Embassy bombings in East Africa, which killed 224 people, including 12 Americans.

Ghailani, who had previously been held by the CIA at secret prisons around the world and at the Guantanamo Bay detention center, was sentenced to life in prison. He is the only Guantanamo detainee to be tried in a federal court.

Among the witnesses against Abu Ghaith is Saajid Badat, who is expected to testify by video link from London that he was planning to bring down a plane with a shoe bomb at the same time that Abu Ghaith was issuing his video decrees.

Badat never carried out the plot and was arrested in 2003 in Britain, where he was in prison until 2010. He previously provided testimony in a New York terrorism case in which a man from Queens was convicted in 2012 of trying to blow up the city’s subway system. In that trial, Badat said he was tasked to detonate the shoe bombs aboard airplanes with Richard Reid, a British citizen.

Badat has refused to come to the United States because he remains under indictment here in the shoe-bomb conspiracy.

Lewin said Abu Ghaith’s threats about the “airplane storms” were “deadly real” and told the jury that the videos would be damning.

“You will literally watch him commit his crimes,” the prosecutor said.

But Cohen said Badat cannot connect his client to the shoe-bomb conspiracy.

Prosecutors also plan to call Sahim Alwan, who was a member of the Lackawanna Six, a group of Yemeni Americans from the Buffalo area who were convicted of providing material support to al-Qaeda. Alwan traveled to Afghanistan briefly and encountered Abu Ghaith at a compound there.

Cohen had also been seeking testimony from the self-proclaimed mastermind of the Sept. 11 attacks, Khalid Sheik Mohammed, who is facing a military commission trial at Guantanamo. The trial is expected to conclude by the end of the month.

Julie Tate contributed to this report.