By Ruthy Munoz

WASHINGTON (Reuters) - The family of Victor White III, a black man who died while in custody of sheriff's deputies in 2014, is calling on the U.S. Justice Department to reopen its investigation after new allegations of widespread abuse by the Louisiana sheriff's office involved in the incident.

The family will make its formal request to U.S. Attorney Stephanie Finley on Friday, lawyer Carol Powell Lexing said on Thursday.

White, 22, died in Louisiana in March 2014, while sitting handcuffed in the backseat of an Iberia Parish sheriff's patrol car. Deputies said he shot himself. White's family contended he had been beaten before he died and that sheriff's deputies "killed him," Powell Lexing said in an interview.

The Justice Department investigated but said the evidence was insufficient to prove any sheriff's deputy had fired a weapon at White.

A federal grand jury last month indicted Iberia Parish Sheriff Louis Ackal on charges he had directed subordinates to harass, intimidate and beat detainees in the local jail in New Iberia, Louisiana, some 100 miles west of New Orleans.

The indictment of Ackal and others in the Iberia Parish Sheriff's Office (IPSO) suggests a pattern of abusive behavior toward detainees that casts the events surrounding White's death in new light, lawyers for the White family say.

Ackal is scheduled to go to trial on Monday. His attorney, John McLindon, said the sheriff is "innocent of all charges" and is "expecting a happy result." A spokesman for the Iberia Parish Sheriff's Office declined to comment.

The effort to reopen the White case comes after a string of high-profile killings of black men by law enforcement officials in various U.S. cities in the past two years. The incidents have renewed a national debate about racial discrimination in the American criminal justice system and given rise to the Black Lives Matter movement.

Earlier this year the U.S. Justice Department announced nine former employees of the Iberia Parish Sheriff's Office pleaded guilty to charges related to alleged beatings of five detainees in the jail's chapel. The alleged incidents occurred in 2011, three years before White's death.

According to the indictment, on several occasions Ackal directed subordinates during staff meetings to "work over" anyone who "sassed" them. He told supervisors he would "take care of" any repercussions from Internal Affairs, the department that investigated complaints of misconduct and excessive force.

White's family contends it was not possible for the handcuffed White to have killed himself and that deputies "took him for a ride" to work him over before arriving at the station.

"Police stations have cameras around them, but on that particular day, at that particular time, the cameras did not work?" lawyer Powell Lexing asked.

The Whites are also being represented by Benjamin Crump, who represented the family of Trayvon Martin, the unarmed black teenager who was fatally shot by a neighborhood watch captain in Florida in 2012.

The Justice Department also found insufficient evidence in that case to show civil rights violations.

(Editing by Matthew Lewis)