Louisiana Gov. John Bel Edwards said Wednesday that the Justice Department’s Civil Rights Division will investigate the fatal shooting of a black man by police in Baton Rouge that was captured on cell phone video.

Edwards said that after watching the video, “I have very serious concerns. The video is disturbing to say the least.”

Cell phone footage shows the confrontation Tuesday between Alton Sterling and police officers. WARNING: Video contains graphic footage. Video by Baton Rouge Crime

A passerby filmed 37-year-old Alton Sterling being wrestled to the ground by two officers on Tuesday. In the 48-second video, someone can be heard shouting, “He’s got a gun! Gun!” One of the officers then holds a gun over Sterling. Soon after, multiple shots are heard.

According to a statement posted by the Baton Rouge Police Department on Facebook, the department received a call from someone reporting that he had been threatened by an armed man wearing a red shirt who was selling CDs outside the Triple S Food Mart.

“An altercation between Sterling and the officers ensued. Sterling was shot during the altercation and died at the scene,” the statement said.

“There is a lot that we do not understand. And at this point like you, I am demanding answers,” said Baton Rouge Police Chief Carl Dabadie at a press conference with Baton Rouge Mayor Kip Holden.

Dabadie identified the two Baton Rouge officers involved as Blane Salamoni and Howie Lake. They were put on administrative leave pending the results of the investigation.

Louisiana Gov. John Bel Edwards announced Wednesday that the Justice Department will investigate the fatal shooting of Alton Sterling. Video by PBS NewsHour

The investigation will be led by the Justice Department in cooperation with the FBI and local law enforcement agencies, Edwards said.

He called for residents to remain calm. “We already have one family torn apart.”

Sterling’s family held a tearful press conference earlier in the day on Wednesday, following protests overnight.

“I will not rest. I will not allow him to be swept in the dirt,” until those responsible are punished, said Quinyetta McMillon, the mother of Alton Sterling’s 15-year-old son, as others sobbed around her and held signs saying “stop killing us.”

“Thank God for YouTube,” otherwise the incident would remain unknown, said Michael McClanahan with the NAACP Baton Rouge.

A local representative of the Nation of Islam called for a boycott of the mall of Louisiana starting on Friday.

Watch Wednesday’s PBS NewsHour report on the incident and more on the life of Alton Sterling.