An attorney who witnessed a horrifying murder-suicide inside a Las Vegas law firm is speaking out – telling her story to Fox News Digital.

Lisa Rasmussen was inside the conference room at Prince Law Group on the morning of Monday, April 8 when fellow attorney Joe Houston pulled out a gun without warning and opened fire.

The terminally ill Houston gunned down prominent Las Vegas attorney Dennis Prince and his wife, Ashley, before turning the gun on himself. The bizarre shooting was the culmination of an "incredibly tense" custody battle with "​​a lot of venom going back and forth," Rasmussen said.

"All of a sudden there's this horrible noise and I couldn't even identify it. It was like a bomb," Rasmussen said, recalling the moment the shooter, who was seated right next to her, began his violent rampage.

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"It was sort of echoing in my head… I had no idea what it was. I turned to my right to kind of look at Joe, maybe, and say, ‘What… what the hell was that?’ And I just see, right next to me, a barrel and a sleeve," Rasmussen said. "I don't even remember seeing the hand. It's so weird. I just saw the barrel of a gun."

Rasmussen said it took her brain a minute to comprehend what was happening.

"I recall Joe standing up and pointing across the table with the barrel – the gun. And by that time, and at that moment, I was really clear on what was happening. I'm like, ‘okay, that was a gunshot. That's a gun. He's pointing it,’" Rasmussen said. "I wasn't going to stand around. I peeled back to my left –  jumped up."

Rasmussen fled the conference room for her life along with her client, an 8-months-pregnant associate and a court reporter. She searched desperately for safety as shots continued to ring out in the conference room. 

When the violence stopped, the gravity of the tragedy became apparent. Joe Houston, 77, had murdered Dennis Prince, 57, and his wife Ashley Prince, 30, Rasmussen said. The Princes were locked in a contentious custody battle with Dylan Houston, Ashley’s ex-husband and Joe Houston’s son. 

Rasmussen was representing Joe Houston’s wife, Kelly, at the time. The group had gathered at Prince Law Group that fateful morning so Kelly could be deposed in the case.

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"People ask me if I think Joe came with a plan to do this, and I say no," Rasmussen said. "I just really think it just unfolded in a moment of rage, whatever. And we're never going to know, right? Because Joe took his own life. We're never going to know what happened."

Rasmussen said Joe Houston displayed no warning signs that morning. She described him as "jovial."

"I was aware that he had a cancer diagnosis, but he did not seem just so, you know, terminally ill," she said. "He was able-bodied, and he had a full head of hair, and he was jovial. He didn't seem sick or even like he didn't feel well. He didn't look pale. He didn't. So he may have had a diagnosis that was problematic. I, of course, have no idea what was going through his mind."

She walked with Joe Houston and his wife up to the conference room where they met several other associates to begin the deposition.

Dennis Prince entered the conference room with his wife, not knowing it would be the last few moments of their lives. Rasmussen said Dennis skipped the usual pleasantries.

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"It was immediately odd because there was no prelude. There was no ‘good morning. Does anyone want water? The bathrooms are in the hall,'" she said. "He just looked at the court reporter and said, ‘please swear in the witness,’ which isn't, you know, the best way to put the witness at ease."

Before the questioning began, Rasmussen said, Joe asked Dennis if there was any way they were ever going to be able to resolve any of the issues for the sake of children.

"And Dennis didn't respond. There was no response to that. He just turned to Kelly and started asking her the deposition questions. And not even, like, normally in a depo, there's some prelude, you know, please wait until I finish my question until you start your answer. There was none of that," Rasmussen said. "He just started asking her the substantive questions, which was, you know, probably not the way most people would do it."

Rasmussen said they only got through three questions before Joe Houston pulled out the gun.

"I didn't see anyone get shot," she said. "It's weird because in the process of, like, looking to my left, watching her answer the question, hearing the noise, kind of going to my right, seeing the barrel, seeing him stand up, going back to my left. My whole memory of across the table is nothing. And I don't know if my mind's blocking it out or if they ducked. I just remember seeing nothing across the table."

Rasmussen told Fox News Digital she is in therapy and thankful for all of the support she has received following the tragedy. She has already returned to work.

"Whether I'm ready to do another deposition is another question, but so far, I'm doing fine," she said. "And I have really been blessed with the support I've received from my community, from other lawyers, from judges. Everyone has been very kind."

Looking ahead, Rasmussen hopes some good can come from the unthinkable tragedy. She hopes to one day share her story with other lawyers to help bring more "respect and civility" back to the profession.

"I hope one day, when I feel a little bit healed from this, to be able to perhaps talk to other lawyers –  to participate in some continuing legal education – to reiterate the importance of civility," Rasmussen explained. "I hope to be a part of the conversation going forward in the future about how much civility matters. It just matters… lawyering should not be a gladiator sport."

Dennis Prince leaves behind four children. He shared an infant daughter with Ashley Prince, his fourth wife.