ORLANDO, Fla. – When Noor Salman's trial begins on March 1, jurors can expect to hear from terrorism expert William Braniff, who will break down the terms, events and people who influenced Pulse gunman Omar Mateen to carry out his attack.
Prosecutors say although Mateen will never face a trial, proving that he was a terrorist is as important in his widow's trial as proving she helped him.
That's where Braniff's testimony will come into play.
He will discuss what Mateen told 911 and hostage negotiators during the deadly June 12, 2016 mass shooting and information that Mateen researched before orchestrating the attack.
Below is a list of terrorists believed to have influenced Mateen.
Abu-bakr al-baghdadi
"(Arabic) I want to let you know I'm in Orlando and I did the shooting," Mateen can be heard on his first phone call to 911. "What is your name? My name is, I pledge allegiance to Abu-bakr al-baghdadi of the Islamic State."
Abu-bakr al-baghdadi is the person whom Braniff testified was the leader of the Islamic State at the time of the Pulse attack from 2015 to 2016.
The first reason why Mateen explained to Orlando Police hostage negotiators why 49 people were being killed.
Abu-Muhhamed Al-Adnani
Abu-Muhammed Al-Adnani was the ISIS spokesman at the time of the attack. Braniff testified Al-Adnani was provocative and emotive as the spokesman on ISIS videos. That included a video, Braniff said, Mateen watched on May 21, 2016 -- three weeks before the Pulse attack.
Federal prosecutors also said Mateen looked up a Reuters article about the same video the next day in which the video called for attacks in Western countries, including the U.S., during Ramadan.
During a phone call with negotiators, Mateen recited nearly word-for-word what Al-Adnani proclaimed in that video, Braniff testified.
"They need to stop the U.S. airstrikes. You have to tell the U.S. government to stop bombing. Are killing too many children, they're killing too many women, OK," Mateen said in a 911 call made during the attack.
Mateen's 'Homeboys'
In those same negotiation calls, Mateen said his homeboys Tamerlan Tsarnaev and Moner Abu-Salha also inspired him.
"My homeboy Tamerlan Tsarnaev did his thing on the Boston marathon. My homeboy Moner Abu-Salha did his thing, OK. So now it's my turn, OK?"
Tamerlan Tsarnaev
Tamerlan Tsarnaev and his brother detonated two pressure cooker bombs that killed three people and injured hundreds of others at the Boston Marathon's finish line on April 15, 2013, according to FBI officials.
Tsarnaev died after his brother ran him over as they were trying to elude authorities in the aftermath of the terrorist attack.
Moner Abu-Salha
Federal prosecutors say Moner Abu-Salha, 22, was a Florida man who in May of 2014, conducted a suicide bombing attack in Syria on behalf of ISIL.
Before that, federal officials say he was part of the November 2015 France attacks, in which 164 people were killed in restaurants, theaters and nightclubs. Officials say Abu-Salha drove into a restaurant as part of those attacks, also claiming his allegiance to the Islamic State.
For more information on what to expect during the upcoming federal trial, visit ClickOrlando.com/NoorSalmanTrial.