COLLEYVILLE, Tex. — An hours-long standoff at a Dallas-area synagogue ended Saturday night after police confirmed that the man who held four people hostage was dead.

“All hostages are out alive and safe,” Texas Gov. Greg Abbott (R) tweeted about 9:30 p.m. local time, after a loud boom and what sounded like gunshots erupted from the area. Colleyville Police Chief Michael Miller confirmed that “the subject is deceased” but declined to say whether had been killed by law enforcement or himself.

The confrontation began during Saturday services at Congregation Beth Israel in this suburb of Fort Worth and Dallas, streamed on the synagogue’s Facebook page for practitioners to tune in from their homes. Police were called about 11 a.m. after a man with a gun and explosives captured four people, including the rabbi, said a law enforcement official, who spoke on the condition of anonymity to discuss the ongoing investigation. One man was released uninjured shortly after 5 p.m.

The law enforcement official said the man’s motive for taking hostages appears to be his anger over the U.S. imprisonment of Aafia Siddiqui, who is being held in federal prison in Fort Worth, for trying to kill U.S. soldiers.

Siddiqui, who was convicted on terrorism charges in 2010 and sentenced to 86 years in prison after opening fire on Americans, has become a cause celebre in Islamist militant circles that have elicited frequent demands for her release.

The hostage-taker is not a member of Siddiqui’s family, her attorney, Marwa Elbially. said before the standoff ended, adding that the family does not know of the individual’s identity or approve of his actions.

“They condemn any type of violence done in [Siddiqui’s] name,” Elbially said. “We’re all praying that this situation ends peacefully and he’s taken into custody.”

As recently as September, British extremist preacher Anjem Choudary announced a campaign calling for Siddiqui’s release.

“The obligation upon us is to either free her physically or to ransom her or to exchange her,” Choudary said on his Telegram channel. “However, until such time as we can fulfill one of these obligations the minimum that we can do is to use all that we have to raise awareness about her case, to keep her name in the hearts and in the minds of Muslims.”

On Jan. 13, a pro-Islamic State outlet released a video in which a narrator denounced what he described as the attacks and torture by “the enemies of Allah” against female Muslim prisoners. A poster mentioning Siddiqui is visible in the background of the video. In 2014, the Islamic State offered to release American hostage Kayla Mueller in exchange for Siddiqui and $6.6 million.

The Pakistan-born Siddiqui, who earned a bachelor’s degree in biology from MIT and a PhD in neuroscience from Brandeis University, was married with three children and living in the Boston area during the Sept. 11, 2001, attacks. She left her husband and returned to Pakistan in 2003, fearing that if she stayed in the United States, her children would be forcibly taken from her and converted to Christianity, according to a psychological report prepared for her trial. The report said that her thoughts were “replete with numerous conspiratorial ideas” and that “she also related a number of beliefs that appeared delusional.”

Siddiqui disappeared after her return to Pakistan. She was captured in Afghanistan in July 2008, when she was found with a flash drive containing documents on chemical and biological weapons, according to U.S. prosecutors. When FBI agents and U.S. military personnel were interviewing her in Afghanistan, she grabbed a rifle and opened fire on the Americans before she was herself shot. She was flown to the United States and convicted in federal court in New York of attempted murder for the attack.

Steven Stalinsky, executive director of the Middle East Media Research Institute, said Saturday’s events at the synagogue were “energizing jihadis and terrorist groups both online and on the ground who haven’t had much to be excited about since the Taliban’s return to power.”

In the Facebook live stream of the Shabbat service, which has since been taken down, a man seemed to be speaking on the phone off-camera, sometimes shouting, sounding increasingly stressed. He said he wanted to speak with his “sister,” seemingly referring to Siddiqui with an expression of solidarity. The hostage-taker is not the brother of Siddiqui, according to two people familiar with the family.

Minutes before the live stream cut off, the man could be heard talking on the phone, sharing chilling words to whomever he was speaking with: “Don’t cry about me. I’m going to die.”

Police said on Twitter that they were “conducting SWAT operations” and asked people to avoid the area Saturday. The FBI, the city of Colleyville and the police department did not respond to requests for comment Saturday. The Texas Department of Public Safety confirmed that the agency had responded to the scene, directing further questions to the FBI.

It is unknown how many people were in the synagogue. The scene unfolded Saturday, when Jewish places of worship typically hold sabbath services.

Police blocked off streets leading to the synagogue Saturday afternoon. Journalists and bystanders had huddled at the parking lot of Good Shepherd Catholic Community.

Among the crowd were members of the Secure Community Network, a nonprofit organization that works with Jewish congregations to prepare for scenarios such as the one unfolding nearby. Chairman Harold Gernsbacher, who lives in Dallas, was called about the situation about 11 a.m.

He said the group worked with the Congregation Beth Israel, including Rabbi Charlie Cytron-Walker, on Aug. 22 to evaluate the perimeter of the synagogue and practice safety drills in case a shooting ever occurred.

“We’re dealing with the fact that antisemitic acts are on the rise across America,” said Amy Korenvaes, a board member of the Secure Community Network.

Anna Salton Eisen, founder and first president of Congregation Beth Israel, described the congregation as “a lot of people who are from other places.” Mostly, she said, it has become a mosaic of individuals from all over the country bound together by the desire to create a community for themselves. From potlucks to worship, “we have become a tightknit, caring family,” she said.

From its origins, the engagement with different faith communities has been central to the congregation’s identity, Salton Eisen said. Before the temple was built, local churches opened their doors and allowed the group to worship in their spaces. Every year, they organize “Peace Together,” an interfaith walk created by churches and mosques. Cytron-Walker himself is known for cultivating “wonderful relationships” with both ministers and imams, she said.

In response to news of the hostage situation, Jewish communities in several cities heightened their security. Police in Los Angeles, Beverly Hills, Calif., and Dallas said they increased patrols around their local synagogues. The law enforcement official who talked to The Post said that early in the standoff, the hostage-taker said he wanted a rabbi in New York to know that he was taking the hostages because he wanted Siddiqui freed. As a precaution, New York police officials sent officers to provide additional security to the synagogue where the rabbi works.

Jewish leaders and others condemned the attack as part of a number of assaults on Jewish people and places of worship. In 2019, an armed shooter killed 11 people and injured six others at Pittsburgh’s oldest synagogue, Tree of Life. Six months later, a shooter killed one and injured three in a synagogue near San Diego.

María Luisa Paúl in Lakeville, Minn., contributed to this report.