The federal probe into the beating of a Pearl River veteran has entered a new phase with FBI agents interviewing members of the Pearl River Police Department this week.

Pearl River Police Chief JJ Jennings confirmed federal agents interviewed him, his Deputy Chief and the officer who initially conducted a welfare check on U.S. Army veteran Chris Cambre, 48.

MORE: Feds looking into beating of Pearl River Army vet by St. Tammany deputies

Cambre suffers from post-traumatic stress disorder, or PTSD, from his year of service in the Iraq War.

As WWL-TV and partner newspaper the New Orleans Advocate first reported, in January, a Pearl River Police Officer went to check on Cambre at the request of his friends after he posted that he was "struggling" having a bad night on Facebook. But the night got much worse for Cambre after five St. Tammany Parish Sheriff’s Deputies arrived.

The Pearl River officer said the deputies shot Cambre with a Taser, then proceeded to beat him with a retractable police baton.

"They were screaming at me to stop resisting, but there was no resistance," Cambre said. "I was laying, pretty much face down, in the mud. My palms were facing skyward. I'll never forget."

Jennings said in an interview last month that he couldn’t believe how the whole thing unfolded.

“I don't understand what he did wrong to deserve to be tased or batoned, but I wasn't out there,” Jennings said.

He was handcuffed and taken to the hospital bruised and bleeding from his jaw, but Cambre was never charged with a crime.

Cambre filed an internal affairs complaint with the St Tammany Sheriff's Office, but he said the sheriff’s office told him two weeks later the case was closed.

“After we found out that the calls, that they decided the case was closed, that their officers handled it properly, then it was handed over to the DA's office and they're actively investigating this case,” Jennings said.

DA Warren Montgomery said he handed the case over to federal investigators to determine if Cambre's civil rights were violated.

“Our deputies followed protocol including the STPSO use of force policy and their training practices when dealing with a non compliant individual,” said Public Information Officer Meredith Timberlake.

The Sheriff said the FBI Civil Rights Task Force was handling the federal review of the case.