iStock/Thinkstock(JEFFERSON PARISH, La.) -- The death of a 22-year-old black man who died in police custody in Louisiana has been ruled a homicide.

Keevan Robinson died last week after he was apprehended by detectives of the Jefferson Parish Sheriff's Office.

Dr. Gerry Cvitanovich, the county coroner, said on Monday that preliminary findings show Robinson suffered severe trauma to his neck consistent with compressional asphyxia.

"We're confident at the end of our process that that is going to be the cause of death," Cvitanovich said. "The manner of death at this point is homicide."

The forensic finding of homicide differs from the legal definition. Police and prosecutors ultimately need to determine whether a crime took place, Cvitanovich added.

Jefferson Parish Sheriff Joseph Lopinto said state police and the FBI are joining in the investigation of Robinson's death.

All four detectives involved with apprehending Robinson are white. They were read their rights and questioned, and put on desk duty, Lopinto said.

Authorities on May 10 had targeted Robinson in an undercover investigation because he was suspected of dealing narcotics, officials said. He fled after spotting detectives while at a gas station, wrecking his vehicle and hopping fences until the four detectives chased him down in a backyard, police said.

During that struggle, Lopinto said, Robinson stopped breathing. He was taken to Ochsner Medical Center but could not be revived, according to officials.

"This incident investigation started on May 10, continues today, and will continue until the completed case report is finalized and presented to the Jefferson Parish District Attorney's Officer for its review," Lopinto said in a statement dated May 14.

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