Baton Rouge Police Chief Murphy Paul released four previously unseen videos of the 2016 shooting death of 37-year-old black man Alton Sterling.
Chief Paul said Lake, who faces a three-day suspension, answered all questions during the hearing at police headquarters.
The disciplinary decisions were announced as the department released officers' body camera footage Friday.
Warning: The videos below are graphic and disturbing to watch.
The decisions are designed "to bring closure to a cloud that has been over our community for far too long", he said.
"These actions were not minor deviations from policy, as they contributed to the outcome to the death of another human being", he said. "This is over. This is the last investigation".
Michael Adams, another of the family's attorneys also spoke, saying he appreciates the courage shown by the new police chief and the mayor, and also that Sterling was not out of control when the officer arrived.
One of the police officers involved in the shooting of Alton Sterling, a black man, has been fired.
Both agencies said there was nothing to show the officers "willfully" violated Sterling's civil rights.
Police have said a.38 caliber handgun was found at the scene. The testimony provided by our officers and witnesses and the recommendation from our board members during the disciplinary hearings.
"Treat our officers with the respect that we deserve", the chief said. "Every officer knows in their heart that they may be called to a higher duty". "Unreasonable fear within an officer is risky", Baton Rouge Police Chief Murphy Paul said.
Paul said Salamoni chose not to answer any questions during BRPD's investigation, per the advisement of his attorney.
Sandra Sterling, the woman who raised Alton Sterling, told CNN she saw the body camera videos before they were released. They also said they are happy Salamoni was sacked, but disappointed that Attorney General Jeff Landry did not allow the case to be presented before a grand jury.
According to sources familiar with the case, Salamoni pointed his gun at Sterling's head and told him he would "blow his f**king head off" if he did not put his hands on a nearby auto.
When Sterling spun around and pulled his right arm away from Salamoni, Salamoni drew his gun, the state report says. As a convicted felon, Sterling could not legally carry a gun.
"Put your hands on the f***ing auto or I will blow your f***ing head off!" Salamoni says, according to the sources describing the video.
Salamoni: "Don't f--ing move or I'll f--ing shoot your ass, b--".
The footage appears to show Salamoni and Lake attempting to subdue Sterling in front of the store.
The announcement comes three days after Louisiana Attorney General Jeff Landry said no charges would be filed against either officer for the shooting, which kicked off a fresh wave of protests, some of which involved the Black Lives Matter movement.
"Given the totality of the circumstances - that the officers had been fighting with Sterling and had attempted less-than-lethal methods of control; that they knew Sterling had a weapon; that Sterling had reportedly brandished a gun at another person; and that Sterling was much larger and stronger than either officer - the Department can not prove either that the shots were unconstitutional or that they were willful", the DOJ concluded.