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BELLEFONTE, Pa. — A detective investigating the case of a Penn State student who died following an alcohol-fueled fraternity event testified on Thursday that someone deleted basement video footage from the night in question.

The testimony came during a fourth day of preliminary hearings as a Pennsylvania judge works to decide if there’s enough evidence to send members of that now-closed fraternity to trial after the death of 19-year-old Timothy Piazza. The first three days of preliminary hearings took place in June and July.

The prosecution asked State College Police Detective David Scicchitano on Thursday, "what happened to the footage in the basement?"

"It appears to have been deleted," he said.

Scicchitano said that all of the footage prior to Feb. 6, two days after Piazza's death, was gone.

It was not immediately clear what the footage would have shown.

The detective added that there was a suspect in part of an ongoing investigation into who deleted the footage, and that suspect was sitting in court during the hearing.

Centre County District Attorney Stacy Parks Miller confirmed to NBC News the detective's testimony that video from a basement camera had been deleted and said the suspects included "at least" someone in the court room on Thursday, potentially leaving the door open for others to be charged surrounding deleting the footage.

She later added that the FBI is helping to try and recover the footage that was deleted from the basement camera, and that the revelation of the deleted footage came within the last week.

Piazza family lawyer, Tom Kline, said, "It's a stunning development to learn that the video tape here actually existed in the basement. We were under the assumption that there was no video tape."

State College Police Detective David Scicchitano, left, is crossed examined by defense attorney Theodore Simon, who is representing Luke Visser in court on Aug. 10 in Bellefonte, Pennsylvania. Christine Cornell

Piazza died on Feb. 4 — two days after falling down a flight of basement stairs in the Penn State chapter’s Beta Theta Pi frat house following a night of heavy drinking, authorities have said.

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Eighteen men are facing charges — ranging from involuntary manslaughter and felony aggravated assault to tampering with evidence — relating to the death.

Sixteen of the accused have appeared in court during the preliminary hearings, and two waived their right to the hearing.

Related: Tensions Flare During Latest Day of Hearing

Security video showing the final hours of Piazza’s life have been just one piece of evidence provided to the judge. While authorities have said there were multiple surveillance cameras at the frat house, the basement cameras did not capture the night in question.

Thursday was the first time it was revealed that the any basement footage may have been tampered with.

Also on Thursday, prosecutors played more video in court in order to show Piazza's condition before he was taken to the hospital. In the video, Piazza walks into the frame appearing to be staggering slightly at first, crosses the room toward the open patio door, and then stumbles and falls near the door. He is shirtless and his pants are falling down. He then collapses onto a couch.

The available surveillance video purports to back up the prosecution's claim that the accused fraternity brothers waited hours after Piazza was severely injured to get help.

Penn State President Eric Barron said in a statement the university was "sickened" by reports of what was shown on the video of Piazza played at previous hearings.

Other pieces of evidence include incriminating text messages that imply fraternity members acknowledge how damaging Piazza's injuries and an accusation of hazing could be for them.

Tensions flared early into the preliminary hearings as the prosecution and defense teams broke out into regular shouting matches inside the courtroom as texts were shown to the judge.

Related: Prosecutors to Show Timothy Piazza's Final Hours at Hearing

One text read that Piazza "looked f-----g dead."

"I think we are f----d. Like beyond f----d," another read.

Additional messages showed the brothers urging new pledges to stay "quiet" about the incident, while even more showed an attempt to allegedly cover up the fraternity’s involvement.

Parks Miller and several attorneys for the accused frat members have engaged in heated arguments throughout the hearings.

Timothy Piazza, center, with his parents Evelyn Piazza, left, and James Piazza, right, during Hunterdon Central Regional High School football's "Senior Night" at the high school's stadium in Flemington, New Jersey. Patrick Carns / via AP file

Ted Simon, the lawyer representing fraternity brother Luke Visser, who is charged with aggravated assault, was the first defense attorney to cross-examine at Thursday's hearing.

He argued that there was no way of knowing how intoxicated Piazza was and that Parks Miller intentionally left out surveillance footage that would have helped his client's case when she played portions of the video in previous hearings.

This was not the first time Simon accused Parks Miller of leaving out pertinent information.

"Play the tape," Simon said last month, accusing Parks Miller of leaving out key portions of evidence.

"Shame on you!" Parks Miller fired back. "(You're) lying to the judge."

Judge Allen Sinclair has seemed reluctant to step in when Parks Miller and defense attorneys have openly clashed during the proceedings.

Ezra Kaplan reported from Bellefonte, Pa. Kalhan Rosenblatt and Daniella Silva reported from New York.