Protests erupted outside of One Police Plaza after another day of testimony in the NYPD disciplinary trial of Officer Daniel Pantaleo, who is accused of putting Eric Garner in a banned chokehold that led to his death.

With the trial winding down, Pantaleo's attorney revealed the officer will not testify in his own defense.

Instead, a transcript of his GO15, the interview he gave to police internal affairs investigators, will be read in court.

"How is they not going to let him to testify? And he is the key factor in this trial," said Gwen Carr, Eric Garner’s mother.

It is unusual for a police officer not to testify in his or her own defense at a disciplinary trial. But Pantaleo's attorney said it would be "reckless" to put the officer on the stand because the Justice Department is still investigating whether to charge Pantaleo with violating Garner's civil rights.

"And they're just going to let him ride it out…and it's never going to be contested? No," said Carr.

During Wednesday's court session, retired Sergeant Russell Jung, who trained Pantaleo at the Police Academy 13 years ago, testified for the defense. He said Pantaleo's takedown of Garner was not the result of a chokehold, but a so-called seatbelt maneuver approved by the NYPD.  

"This was one of the first times where the department had to face the fact that this police officer went out and did what he was asked and how he was trained," said PBA President Pat Lynch.

Garner's mother dismissed the sergeant's testimony.

"The whole world seen that it was a chokehold. They're trying to say my son caused his own death," said Carr.

Another defense witness, Dr. Michael Graham, the chief medical examiner in St. Louis, said Garner's death was caused by a preexisting heart condition. This contradicts New York City's medical examiner, who blamed the alleged chokehold.

A Staten Island grand jury declined to indict Officer Pantaleo on any criminal charges. If found guilty in the departmental trial, he could be fired.