(CNN) - A 22-year-old black man killed after a struggle with Jefferson Parish, Louisiana, authorities likely died of asphyxiation, the coroner said Monday.
While conceding his officers used force on Keeven Robinson, Sheriff Joseph Lopinto said he has not concluded that his deputies administered a chokehold on the man during his apprehension.
Robinson, who was from Metairie, just outside New Orleans, died Thursday following a police chase and altercation with narcotics detectives, according to authorities. Dr. Gerry Cvitanovich, the Jefferson Parish coroner, has ruled his death a homicide.
An initial autopsy found significant traumatic injuries to the soft tissue of Robinson's neck, Cvitanovich said, cautioning that the results from the autopsy, conducted Saturday, are preliminary and more tests need to be conducted.
The findings, the coroner added, are consistent with compressional asphyxia, which will likely be the ultimate cause of death.
Robinson's death is one of the latest in a string of nationwide incidents involving police being accused of using excessive force against black men and teens.
The four detectives involved are white, said Lopinto, who declined to release their names.
"I understand ... this investigation will be under a microscope, understand it fully," Lopinto told reporters.
Gaylor Spiller, president of the West Jefferson Parish NAACP branch, said Robinson's family is seeking an independent autopsy.
"I like the fact that Sheriff Lopinto stepped up to plate, and he's doing his part," Spiller said, according CNN affiliate WDSU. "He knows that the NAACP will be on his trail."
Robinson was being investigated by narcotics detectives early Thursday, said Lt. Jason Rivarde, spokesman for the Jefferson Parish Sheriff's Office.
Undercover detectives assigned to the case tracked Robinson down at a local gas station and tried to arrest him, Rivarde said, but Robinson jumped in his vehicle and led police on a chase after spotting them.
The suspect rammed several police cars before crashing his vehicle, he said.
Robinson took off on foot, jumping several fences before deputies caught him in the backyard of a nearby residential neighborhood, Rivarde said.
A struggle ensued, the lieutenant said, with deputies eventually handcuffing Robinson. Once Robinson was in handcuffs, detectives noticed Robinson was not breathing, he said. Detectives administered life-saving techniques before Robinson was taken to a local hospital, where he died, he said.
The agency is not equipped with body cameras or dash cameras, according to Rivarde.
"They were in a struggle," Lopinto said. "They used force."
The officers admitted to using force during the arrest, the sheriff said, but he's "not coming to the conclusion that this was a chokehold."
Lopinto said he contacted the Louisiana State Police on Saturday after learning of the initial findings, and he asked the department to assist in the investigation.
The sheriff said he has "every faith" in his officers to do their job well.
"I know they have the expertise because this is what they do every day, but I also understand that an independent set of eyes is something that's appropriate in a case like this," he said.
The four detectives involved in the arrest were read their rights and have given statements, Lopinto said.
They are being reassigned to administrative duty pending the outcome of the investigation, the sheriff said.
The FBI's Civil Rights Task Force, which the sheriff also contacted Saturday, is looking into the matter as well, Lopinto said.
Robinson's family praised Cvitanovich on Monday. Family attorney Hester Hilliard thanked the coroner's office "for their professionalism and their transparency."
"Today is just as hard as Thursday for this family. They're grieving, and today they had to find out that Keeven lost his life at the hands of another," she said, according WDSU. "And that's very, very hard for them."
"Now, it's time for us to move on to making funeral arrangements for a 22-year-old that should not have died."
In an interview with CNN, Hilliard said she is hoping "to see the same justice for Keeven as with any other individual who has died at the hands of someone other than the police. ... We are hoping for a thorough investigation, an arrest and prosecution of those that caused his death unjustifiably."