(NewsNation) — As Alex Murdaugh’s son, Buster Murdaugh, testified in his father’s murder trial, at times Alex would beam with pride. At other times, he cried heavily while Buster Murdaugh talked about the night his mother and brother had been killed.

Susan Constantine, a jury consultant and behavioral analysis expert, said on “Morning in America” that during the trial, it’s important to look at what is being stated, how Buster Murdaugh responds and how Alex Murdaugh is emoting.

“All of that tells the story,” Constantine said. “Those are what we call points of interest.”

For instance, Constantine said, Alex Murdaugh held a lot of emotion in his mouth.

“You see him pushing his tongue around. His jaw will move, you’ll even see kind of some tensing right here,” she said. “This is all indicative of a lot of emotional stress.”

Watch the entire interview in the full video above.