Former FBI Response Team member explains how authorities will process El Paso evidence

Former FBI response team member Maureen O'Connell detailed on Saturday to Fox News how federal law enforcement officials will examine evidence following the deadly shooting at a Walmart in El Paso, Texas, that left 20 dead and 26 injured.

Anchor Leland Vittert said federal authorities had left the bodies of the victims inside the store for more than 10 hours after the shooting and asked what they will have to do to ascertain vital evidence going forward.

"Part of that has to do with the trajectory of the rounds that were fired and the bodies have to remain in place until they can really get those details down in a way that can be used in a court of law. And the evidence will have to be packaged properly," she replied.

"They're going to have to measure the way the victims fell and try to figure out exactly where the coward was standing when he fired all of those rounds. It’s a very laborious task but it's the most important one because the evidence has got to be done right, and the FBI's ERT team will always do it right."

El PASO SHOOTING EYEWITNESS DESCRIBES HIDING WITH 'HUNDREDS' OF PEOPLE IN BACK OF WALMART

O'Connell also said authorities will be searching the suspect's home to determine if they can link him to the crime, but claimed the process of building an official case will take more time.

More from Media 

"[They] would then go through the room and clear each room, which takes a bit of time and then when the rooms are all cleared and it’s ... safe enough for the ERT team to go in, then they go in. They mark each and every room and every piece of evidence is photographed in place, identified, logged and then packaged," she said.

"Again it’s very laborious and very meticulous. But it is really important, impactful work and the gravity of that is understood by the team and they know it’s going to be a long night. They could be in there all night long depending on what they find. If they are finding ammunition and rounds and -- he could have had the whole basement to himself."

FOX NEWS REPORTER GIVES EMOTIONAL ACCOUNT OF VICTIM SAYING HIS MOTHER IS DEAD, FOLLOWING EL PASO SHOOTING

CLICK HERE TO GET THE FOX NEWS APP

The suspected gunman murdered 20 people and injured 26 on Saturday, after he calmly walked into the store and opened fire, Texas, state and city officials said.

The suspect has not been publicly named, but two law enforcement officials identified him to The Associated Press as 21-year-old Patrick Crusius of Allen, Texas.

Investigators have examined a manifesto that may have been written by the shooter which would indicate a “nexus to a hate crime." The suspect is expected to face capital murder charges.

Gov. Greg Abbott, R-Texas, and President Trump have been briefed on the shooting and are in direct contact with one another, with Trump pledging the "total support" of the federal government.

Fox News' Lucia I. Suarez and Bradford Betz contributed to this report