STATE COLLEGE, Pennsylvania -- Surveillance video that was deleted -- then recovered -- led to new charges Monday in the hazing. The Penn State University sophomore died in February after falling down stairs during a night of heavy drinking while pledging for the Beta Theta Pi fraternity.
The deleted material showed what took place inside a fraternity's house basement the night Piazza died. District Attorney Stacy Parks Williams said at the same time police were trying to obtain it, a fraternity member was erasing it.
"We know exactly the time it was deleted, and the police were indeed in the house," Williams said.
The new evidence means 12 additional fraternity members now face charges -- five with felonies, including involuntary manslaughter and aggravated assault, and others with misdemeanors, including hazing and furnishing alcohol to minors.
Police said Piazza drank 18 drinks in one hour and 22 minutes.
"Never once obtained one of those drinks for himself, brothers were coming up to him and giving him those drinks, including in the basement," Williams said.
"We are making holiday plans without our son, Tim," his father, Jim Piazza said.
Jim and Evelyn Piazza said the new evidence gives them hope, but it hasn't eased their grief.
"Why are you putting yourself through all of these appearances, press conferences and interviews?" CBS News asked.
"It is really important for people to see the damage, the far-reaching damage, that has occurred because these young men decided to protect themselves instead of Tim. They have destroyed so much, they have destroyed our joy," Evelyn Piazza said.
"We need parents talking to their kids about this. We need parents to put their foot down and say, 'You must not do this.' We need parents to stop encouraging their children to get involved in fraternity antics like hazing," Jim Piazza said.
One fraternity member's attorney said evidence will show his client is not responsible. Meanwhile, the D.A. on Monday refiled a charge of tampering with evidence against the young man she says deleted that video.