Update at 5:06 p.m. Pacific on Friday, May 19, 2016: The obstruction case against 17-year-old Christian Aguilar has been dropped.
Pomona police officers claimed Aguilar was resisting arrest during a confrontation at the Los Angeles County Fair on Sept. 15.
Late Friday afternoon, a judge dismissed the charges against Aguilar.
Top news of the day
Earlier: Twenty four hours since an NBC4 investigation into a video recording showing a confrontation between Pomona police and a teenager at the Los Angeles County Fair, the family's attorney says police can't prove the boy's father was drunk and explains the critical evidence he says is missing.
When a family accusing the Pomona Police Department of a cover-up after an assault of their teenage son by officers appears in court on Friday, no doubt they will be trying to comprehend why their family night out escalated to a confrontation.
The family of Christian Aguilar alleges police punched, then hit their son with a baton. He was taken to the emergency room by police, suffering from a concussion, bruises and nerve damage to his jaw. His mother remembers picking him up from police at the emergency room.
"I couldn't do anything and I'm like, 'You couldn't, Christian. They would have killed you,'" said his mother, Erain.
As law enforcement herself for 15 years, Erain Aguilar said the family lives with a healthy respect for rules that includes both Christian and her husband.
Ignacio was a junior police officer with the Pomona Police Department, the very department charging him with public intoxication.
"I said I had a beer and a half," Ignacio said. "Can you give me a field sobriety, at least a Breathalyzer?"
Attorney David Gammill says Pomona police will not be able to prove Ignacio was drunk, even though police reports say he had slurred speech and an "inability" to take care of himself.
"They didn't take his blood alcohol and they haven't turned over a video of him in custody in the jail," Gammill said.
He walked out of the Pomona Fairgrounds on his own two feet and Christian's video shows him walking fine, said Gammill. There is no allegation that he needed help getting out of the fair.
Ignacio noticed security cameras in the drunk tank. As a specialized cardiac nurse he has some knowledge of blood alcohol levels – and was desperate to prove he wasn't intoxicated.
"I was doing my own field sobriety," Ignacio said. "I was balancing on one leg. I was balancing on the other with my head back and touching my nose."
Gammill is hopeful Pomona police will turn over that jail cell video at Ignacio's hearing Friday morning.
At the hearing a judge could rule if Chrisitan Aguilar is guilty of resisting arrest.