Cytron-Walker may not have known immediately that Malik Faisal Akram, 44, was a British citizen. Akram had arrived in the United States via New York's John F. Kennedy International Airport in late December, a U.S. law enforcement source familiar with the investigation told CNN.
In the two weeks before he met Cytron-Walker, Akram had spent three nights - Jan. 6, 11 and 13 - at a homeless shelter in Dallas, according to Union Gospel Mission Dallas CEO Bruce Butler. He was very quiet and was not there long enough to build any relationships, Butler said.
Over their common tea, Cytron-Walker and Akram spoke, the rabbi said.
"Some of his story did not quite agree, so I was a little curious, but that is not necessarily an uncommon thing," said the rabbi, who soon after the same day would lead a service for the 157 families in his congregation. , established in 1999.
The rabbi pointed to Jeffrey Cohen, the vice president of the synagogue's board, as their guest that day. Cohen went over and introduced himself, he wrote in a Facebook post in which he described his experience.
"He was talking on the phone, but briefly stopped his conversation," Cohen said. "He said hello, smiled, and after we introduced ourselves, I let him go back to his call. He seemed calm and happy to be with from the cold 20 degree morning. His eyes did not dart around; his hands were open and calm, he said hello, he smiled. "
As the rabbi led the prayers - his back turned as he turned toward Jerusalem - he heard a click. It came from the stranger.
"And it turned out to be his gun," Cytron-Walker said.
Cohen said he heard the same click, "the unmistakable sound of an automatic slide engaging a round." The mysterious guest then began to shout something. Cohen called 911 on his phone, laid the screen down and moved as commanded, he wrote.
Akram took four people hostage, including the rabbi, authorities said.
'I'm going to die at the end of this'
Police received an emergency call at 10:41 p.m.
They rushed to the synagogue and set up a perimeter and evacuated nearby residents, police said. Soon, nearly 200 local, state, and federal law enforcement officers, including the FBI and the Federal Bureau of Alcohol, Tobacco, Firearms and Explosives, were present, said FBI Dallas Special Agent Matthew DeSarno.
"I'm shot. I'm ammunition," he told a man he called a nephew. "Guess what, I want to die,"
The sound can be difficult to understand and it is not clear who Akram is talking to. But it is clear that he planned to die during the conflict, he repeatedly told people.
"OK, are you listening? I do not want you to cry. Listen! I want to release these four guys ... But then I'm going out into the yard, yeah? ... And they" are you going to take me, okay? I'm going to die at the end of this, okay? Are you listening? I'm gonna die! OK? So do not cry over me, "the man said to another.
Ward Stacey Silverman watched the livestream for more than an hour. She heard the suspect shout, sometimes alternating between saying, "I'm not a criminal," to apologize, she said.
The man staggered between the languages and "screamed hysterically," she said. He claimed to have a bomb.
She was not involved in the Colleyville attack, her lawyer said Saturday.
"He wanted this woman released, and he wanted to talk to her, and he thought - yes, he said straight - he chose this synagogue because 'Jews control the world. Jews control the media. Jews control the banks. I want to talk to chief rabbis in the United States, "Cohen told CNN, adding that there are no chief rabbis in the United States.
Inside the synagogue, Cohen resisted following exactly as Akram commanded, he wrote in his Facebook post. Instead of walking to the back of the room as ordered, Cohen remained in line with one of the exits. When a police officer came to the door and the hostage-taker became more agitated, Cohen moved closer to the exit door, he wrote.
Akram had them call their families, and Cohen called his wife, daughter and son and even wrote on Facebook. He also slowly moved a few chairs in front of him - "all to slow down or divert a bullet or shrapnel," he wrote.
At one point - at the suspect's request - the rabbi held hostage called a well-known rabbi in New York City so that the suspect could say that Siddiqi had been led into suspicion and that he wanted her released, he said. two officials who were briefed on the investigation.
As hours ticked by, law enforcement dealers had a "high frequency and duration of contact" with the suspect, DeSarno said. The FBI called its hostage rescue team from Quantico, Virginia, and about 60 to 70 people came to the scene, Colleyville Police Chief Michael Miller said.
A hostage - a man - was released unharmed around noon. 5 p.m., Colleyville Police Sgt. said Dara Nelson. The hostage-taker did not injure the hostages, the rabbi told CBS.
But, he added, they were threatened all the time.
A folded chair activates a bold escape
As Saturday afternoon rolled into the night - and the hostage - taker's behavior began to change - that training helped the rabbi and the other two who were still holding against their will.
"In the last hour of our hostage crisis, the gunman became more and more belligerent and threatening," Cytron-Walker said Sunday in a statement. "Without the instruction we were given, we would not have been prepared to act and flee when the situation arose."
Cohen helped another hostage move closer to that exit and whispered to him about the door, he wrote. The third hostage later joined them when they received pizza to eat, placing them all within 20 feet of the front door.
They talked to Akram and asked him questions in an attempt to buy the FBI time to get into position, he wrote.
Nevertheless, the situation began to develop. "At one point our attacker instructed us to get on our knees. I got up in my chair, stared sternly at him. I think I slowly moved my head and said NO. He stared at me and then moved me. "to sit me down. It was this moment that Rabbi Charlie shouted, ran," he wrote.
The rabbi said he threw a chair at the hostage-taker to make time.
"We were horrified," Cytron-Walker told CBS. "And when I saw an opportunity where he was not in a good position, I made sure that the two gentlemen who were still with me were ready to go.
"The exit was not too far away. I asked them to go. I threw a chair at the gunman and I walked towards the door," he said. "And we were all three able to get out without a shot being fired."
A group of heavily armed police officers moved towards another part of the building, the video shows. About 30 seconds later, a series of four blasts erupted, followed by a more powerful explosive boom that caused a series of car alarms to start complaining. Other armed law enforcement personnel moved into another position by the building, and three more loud bangs followed, the video shows.
The loud boom that was heard by a CNN team near the synagogue around 6 p.m. 21.12, was the result of access tools used by the hostage rescue team, an ATF spokesman said.
The rescue squad broke into the synagogue, Miller said. The suspect was killed.
None of the four hostages were injured, DeSarno said.
Several barriers resonated as the tactical team disposed of remaining entry explosives brought by the rescue team. Investigators at the scene found a firearm that they believe belonged to the suspect, the ATF spokesman said. An ATF dog found no more explosives, the spokesman said.
On Facebook, Cohen credited active shooting training he received for his survival and escape.
"We were not released or liberated," he said. "We got away because we had training from the Secure Community Network in what to do in the event of an active shooting."
The Secure Community Network describes itself as the "official security and safety organization for the Jewish community in North America."
'The time to heal our society has begun'
On Sunday morning, Cytron-Walker took to Facebook, this time to express his gratitude to those who supported him during Saturday's ordeal.
"I am grateful and filled with appreciation for all the guards and prayers and love and support, all the law enforcement and first aiders who took care of us, all the security training that helped save us," he wrote in the Facebook post. .
"I'm grateful for my family. I'm grateful for the CBI community, the Jewish community, the human community. I'm grateful we did it. I'm grateful to be alive," Cytron-Walker said in the post .
There is no indication that the threat from Akram continues, officials said. The investigation into the case and its motive is likely to be global, DeSarno added, including contacts with Tel Aviv and London.
Initially, the FBI found, based on its exchanges, that the suspect was "simply focused on one topic and it was not specifically related to the Jewish community, but we will continue to work to find motive," DeSarno said.
On Monday, the agency called Saturday's attack "a terror-related affair in which Jewish community was targeted," according to a statement. The case "is being investigated by the Joint Terrorism Task Force."
The Beth Israel congregation held a special service Monday night where the rabbi spoke about the need to heal after the incident.
"Thank God, thank God," Cytron-Walker said. "It could have been so much worse and I'm overflowing, really overwhelmed with gratitude."
CNN's Keith Allen, Melissa Alonso, Tina Burnside, Josh Campbell, Kacey Cherry, Ashley Killough, Ed Lavandera, Raja Razek and Geneva Sands contributed to this report..