BATON ROUGE- The bar will be high for prosecuting two police officers in the Alton Sterling case, a former federal prosecutor said Thursday.

"You have to show there was a deprivation of rights, the standard is high, but it's just as high in a murder case," said former U.S. attorney Don Cazayoux.

On Tuesday 37 year-old Alton Sterling, a black man, was shot to death by two white Baton Rouge police officers, Blane Salamoni and Howie Lake II. The next day Governor Edwards and East Baton Rouge District Attorney Hillar Moore announced the case would be handled by federal authorities.

A thorough investigation has been promised but experts like Cazayoux say that doesn't guarantee the two officers will face criminal charges.

"Basically in this case you have to show that they were guilty of murder," said Cazayoux.

Under federal law, U.S. attorneys must prove Salamoni and Lake specifically intended to use excessive force and deprive Sterling of his constitutional right to due process.

But even if federal prosecutors don't press charges, the evidence gathered can be turned over to the EBR District Attorney's office for a murder or a manslaughter case. Those charges would come with their own high standards because the defendants would be police officers.

Before shooting, Salamoni and Lake fought to subdue Sterling when one of them shouted "Gun!" and the other drew his weapon.

Under state law, prosecutors must prove the two officers had no reason to feel threatened or prove they acted with gross negligence.

"What's important is the perspective of the officer at the time," said Mark Spencer with Judicial Watch, a conservative watchdog group. "What would a reasonable police officer do at that time? That [question] is the standard of the court."

Others legal experts believe Salamoni and Lake's guilt is already apparent based on the disturbing video of Sterling's death that is circulating social media.

"The video speaks for itself," said state representative and defense attorney Ted James. "Probable cause is there for an arrest, period."

James said there's already enough evidence for murder charges to be filed. He added the officers shouldn't be allowed to use fear as a defense since they had Sterling on the ground when he was shot.