NASHVILLE, Tennessee (AP) — Four of five former Memphis police officers charged in the killing of Tyre Nichols, a black man who was handcuffed, brutally beaten and ignored by first responders for crucial minutes despite being barely conscious, can no longer work as law enforcement in Tennessee.

The Peace Officer Standards & Training Commission, voted Friday to decertify Demetrius Haley, Emmitt Martin and Justin Smith. The state panel also approved the decision by Desmond Mills to surrender his certification.

The former officers have 30 days to appeal.

The beating of the 29-year-old black man happened during a late night traffic stop January 7. The commission subsequently released documents showing that Haley dragged Nichols from his vehicle and never explained why he was stopped, and that he also took photos of Nichols slumped against the car after he was pummeled by officers and sent the pictures to colleagues.

Nichols died at a hospital January 10.

Early police accounts minimised the violence of the traffic stop — accounts since disproven by witness statements and police and surveillance video — and their specialised unit was disbanded. Two Memphis Fire Department emergency medical workers and a lieutenant were also fired.

The five former police officers charged with second-degree murder have all pleaded not guilty.

The Memphis Police Department requested the decertification of seven of the former Memphis officers involved, including one who retired before he could be fired.

None of the fired officers or their attorneys attended their hearings before the commission on Thursday or its vote on Friday.

Mills' attorney said his client had been wrongly indicted and was "focusing on his freedom."

"It's a waste of time," attorney Blake Ballin said of the decertification attempt. "It is meaningless to him at this stage in his life."

An attorney for Haley declined to comment on the decertification vote. Attorneys for Martin and Smith did not immediately respond to phone messages seeking their comments.

In a letter included in the file seeking his decertification, Smith defended his conduct, stating that Nichols was "violent and would not comply."

The fifth former officer charged, Tadarrius Bean, has not yet had his decertification hearing before the commission. Neither have two former officers who were not charged: Preston Hemphill, who was terminated after firing a stun gun at Nichols during the traffic stop; and Dewayne Smith, the supervising lieutenant who arrived on scene after the beating, who retired instead of being fired.

A seventh police employee who was fired has not been publicly named.

During Nichols' funeral, Vice President Kamala Harris urged lawmakers to approve the George Floyd Justice in Policing Act, a broad package of reforms that includes a national registry for police officers disciplined for misconduct, a ban on no-knock warrants and other measures.