The departmental trial of Officer Richard Haste in the death of Bronx teenager Ramarley Graham opened Tuesday with police prosecutors accusing the officer of not following NYPD guidelines and tactics.

They said the cop should not have entered the teen's home without calling for specialized backup.

"He broke into my home, he shot my son, in front of his brother," said Graham's mother Constance Malcolm. "A 6-year-old, and his grandmother."

NY1 was the first to obtain this surveillance video of Graham entering his East 229th street home with cops chasing him.

Haste has said he thought the teen was armed when he and Officer John Mcloughlin kicked in a second floor door. Haste shot the teen in his bathroom. But no gun was ever found, only a small amount of marijuana.

"Ramarley Graham did nothing, but walk down his own block," said City Councilman Andy King. "Ramarley Graham did nothing, but be a young, black man in the Bronx."

But Haste's attorney suggested the officer was a hero trying to get guns off the street. He called the case tragic.

"His state of mind was that there was a loaded firearm in the possession of the individual he was chasing," said Haste's lawyer, Stuart London. "And I think we had to witnesses here today that drove that point home."

Two black officers, Andrew Jarvis and Tyrone Horne testified Tuesday that they definitely saw a gun. And alerted other officers.

The teen's mother says that's an outrage.

"It is five years later, where is the gun?" she asked. "Where is the gun?"

An indictment of Haste was tossed out because of a prosecutorial mistake. A second grand jury did not indict.

And the Justice department decided against bringing federal civil rights charges.

"We’re here because we’re looking at the tactical flaws that led to someone’s death," said Royce Russell an attorney for the family. "That is the lowest standard that we could ever."

Ramarley Graham's family and their supporters say there were a number of officers on the scene that day and they believe all of them should be fired.

The NYPD is looking to fire Haste who remains on modified duty without a gun. He is expected to take the stand this week.