All four people who were held hostage at a synagogue in Colleyville, Texas on Saturday are "alive" and "safe," the authorities said as media reported gunfire and sounds resembling that of an explosion at the scene.

Though one male hostage had been released unharmed earlier on Saturday, the three remaining hostages were not able to leave until an FBI rescue team, which had flown in from Quantico, Virginia stormed the building following a 12-hour standoff with the suspect.

Shortly after CNN reported that "a loud bang, followed by a short blast of rapid gunfire" came from the synagogue, Texas Governor Greg Abbott announced that all of the hostages were now "out alive and safe."

Colleyville Chief of Police Michael Miller confirmed that the suspect was “deceased” at a press conference late on Saturday. Noting that the man did not harm hostages “in any way," Miller refused to identify him.

"We have identified the subject but we are not prepared to release his identity or confirm his identity at this time," he added. The man's identity has since been made public.

The suspect at one point had reportedly threatened to kill the hostages if anyone entered the building and said he had planted bombs in several locations. However, he also reportedly said he did not want to hurt anyone, and subsequently let one of the hostages escape unscathed.

His negotiations with law enforcement were partially broadcast live on Facebook.

Miller said that although there is no ongoing threat to the synagogue, bomb squads were deployed to the scene to clear it of any potential explosives.

Several US media outlets, including ABC News and NBC News, reported that the man had referred to Aafia Siddiqui, a Pakistani neuroscientist serving an 86-year sentence in the US, during his talks with the negotiators. The man apparently referred to the woman as his “sister. However, the lawyer for her biological brother, Muhammad Siddiqui, told the US media that he had nothing to do with the incident.

Moreover, an attorney representing Aafia Siddiqui later confirmed that the suspect was not her client's brother, and claimed that the woman herself did not endorse the act.

"We strongly condemn the hostage-taking at Congregation Beth Israel in Colleyville, TX… Whoever the assailant is, we want him to know that his actions are condemned by Dr. Aafia and her family,” attorney Marwa Elbially told CNN in a statement on Saturday.

Speaking at the press conference, the special agent in charge of the FBI Dallas Field Office, Matthew DeSarno, admitted that the suspect “was singularly focused on one issue” and that “it was not specifically related to the Jewish community.”

However, DeSarno stopped short of either confirming or denying reports that the man had demanded the release of the Pakistani scientist. “We're continuing to work to find a motive,” he said.

US President Joe Biden, however, appeared to suggest that anti-Semitism might have been behind the attack.

In a statement, Biden said that though “there is more we will learn in the days ahead about the motivations of the hostage-taker,” the United States “will stand against anti-Semitism and against the rise of extremism in this country.”

Siddiqui had been arrested in 2008 after her botched interrogation by the US military in Afghanistan. The woman was initially detained by the Afghan forces after they reportedly found a note on her mentioning a “mass casualty attack” along with a list of several key US locations. Just as her interrogation was about to start, Siddiqui reportedly grabbed a rifle of one of the US soldiers and attempted to fire at a team of US investigators. Although the woman missed the target, and was ultimately shot in the stomach by a US soldier, she was extradited to the US on charges of attempting to murder US nationals in Afghanistan.