BELLEFONTE--A basement camera inside the Beta Theta Pi house at Penn State previously had been described as not-functioning, but a police detective testified Thursday that a member of the fraternity had deleted footage from the camera two days after Tim Piazza died.

The revelation came out during questioning of State College Police Detective David Scicchitano, who said he believed he knew the identity of the person who deleted the footage on Feb. 6. All footage of the basement prior to Feb. 6 then vanished, Scicchitano said, before police could collect it.

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Scicchitano said one of the 18 fraternity members already facing charges in connection to the death of Piazza, 19, was the person who deleted the video. But the detective did not reveal the name in court.

Prosecutors indicated the police would be filing additional charges.

The deleted video from the basement could have captured drinking at a social event with members of a banned sorority, which followed an alcohol-chugging obstacle course upstairs for pledges seeking to join the fraternity on Feb. 2.

It's unclear whether the camera was in a position to capture Piazza's fall down the basement stairs and the aftermath, moments that have been highly debated during the criminal proceedings. Piazza also spent his final hours at the house in the basement before members of the house brought him upstairs about 10 a.m. Feb. 3.

Police went to confiscate the cameras on Feb. 6, but waited to get a search warrant before observing what was available through the cameras.

Centre County District Attorney Stacy Parks Miller said it was learned just a few days ago that there is footage on the basement cameras, previously believed to have been inoperable. The discovery came through ongoing IT analysis in the case, she said.

"There were functioning cameras (in the basement) and they were deleted."

Parks Miller said she is not sure that recovery effort will be successful.

The bombshell about the camera being tampered with was among a few bits of new information at day four of the preliminary hearing for the Beta fraternity members facing charges ranging from involuntary manslaughter to furnishing alcohol to minors.

Ted Simon, attorney for Luke Visser, also brought out what he said was new information that Piazza may have tripped over a girl sitting on the stairwell to the basement. He sought to portray the fall as more of an accident, than anything related to alcohol intoxication.

He asked the detective if he had identified the girl, and potentially a second girl on the stairs and interviewed them. Scicchitano said he had not.

"Why not? Simon asked.

"They weren't wearing name badges," the detective said, adding that the girls should come forward and identify themselves to police.

Centre County District Attorney Stacy Parks Miller pushed back at Simon's assertion that Piazza's death was simply a tragic accident. Even if someone's presence on the stairs contributed to the fall, or if Piazza slipped on a wet floor, Parks Miller said Piazza's drunken state remained a direct cause of his death and the people who provided and plied him with alcohol were responsible.

Simon was the only defense attorney to ask questions Thursday before the proceedings broke for lunch just before noon.

Thursday's hearing represented the continuation of three days of prior hearings during which six defense attorney tried to poke holes in the state's case.

Clear themes have emerged, as most defendants have tried to paint as narrow a picture as possible of their clients' interaction with Piazza, an engineering student from Lebanon, N.J.

UPDATE: This article was updated to add comments from Parks Miller and to clarify the date that police obtained the video system to Feb. 6.

Staff writer Charles Thompson contributed to this report.