BATON ROUGE - The mother of Ronald Greene, with the support of the NAACP, penned a scathing letter to Louisiana State Police demanding the arrest of Lieutenant Colonel Doug Cain after the WBRZ Investigative Unit uncovered documents showing that the high-ranking trooper had a hand in the cover-up surrounding Greene's death in police custody.

Watch Nakamoto's report here

The letter from Mona Hardin, Greene's mother, lambasts Cain and likens the agency to a "gang" for its efforts to conceal what happened to Greene. 

"Doug Cain belongs in jail; instead, your agency promoted him to Lieutenant Colonel and increased his pay," the letter reads in part. "But for the brave actions of Troopers like Carl Cavalier and Albert Paxton who spoke out against my son's injustice, I would still believe that my son died in a single-car crash. The world now knows that narrative to be untrue."

Greene, a Black man, was beaten and tased after a wreck in the Monroe area back in 2019. Family members were told Greene died in a crash, but video showed he was still alive when troopers dragged him from his vehicle after it crashed.

Click HERE to read the full letter from Mona Hardin.

"Knowing that this man could participate in the cover-up of her son's brutal murder and still be at work, that's almost something you can't make up," Eugene Collins with the Baton Rouge NAACP said. "That's why the NAACP is sitting here today calling for Lieutenant Colonel Doug Cain's resignation."

State Senator Katrina Jackson represents the district in Monroe where Greene died. She wants to see Cain and others who played a role in the cover-up fully investigated. She said she's read the notes that were referenced in the WBRZ Investigative Unit story Wednesday night and believes investigating troopers Albert Paxton and Scott Brown who noted the cover-up.

"I don't have confidence in State Police to investigate itself," Jackson said. "Not even for employees...until we know who all was involved in all these cover-ups. It's not just Ronald Greene."

Collins said he's spoken to Mona Hardin who has waited nearly three years for justice for the death of her son. He said this is like a slap in the face to her.

"Mr. Cain should not be in that role. Every time you go to work you are spitting in the face of that family, spitting in the face of Ms. Mona Hardin who has traveled to Louisiana time and time again expecting a grand jury indictment and that has not come."

The governor's office released the following statement Thursday in response to the WBRZ Investigative Unit's story: 

"The Ronald Greene case is under investigation and the Louisiana State Police continue to cooperate with all aspects of the investigation. The Governor expects nothing less and continues to have confidence in the leadership at Louisiana State Police."

Read the statement from the Legislative Black Caucus below.

As it has done in the past, the Louisiana Legislative Black Caucus (LLBC) continues to monitor the details and investigation surrounding the tragic and senseless death of Mr. Ronald Greene.

The LLBC maintains its belief that there are systemic problems and serious concerns that need to be addressed within the Louisiana State Police (LSP).

The LLBC membership is aware of and disturbed by recent information shedding more light on the involvement of Lieutenant Colonel Doug Cain in the investigation surrounding Mr. Greene’s death.

As we process this information, our membership remains vigilant in our commitment to seeking needed policy changes as well as transparent communications from Louisiana State Police and accountability. We also continue to stand with Mr. Greene’s family in their fight for answers and justice.

Additionally, a letter was drafted by the LLBC to the Department of Justice requesting the federal government do a methodical investigation and review of the pattern and practices of LSP with results to be expedited to the LLBC. We will not stop until justice is served.