The Los Angeles County Sheriff's Department said Tuesday that a man fatally shot by a deputy last month wasn't the carjacking suspect they were seeking.

The department said in a statement that deputies encountered 27-year-old Donnell Thompson, who was black, shortly after the carjacker crashed the stolen vehicle, fled into a neighborhood and was arrested early on July 28.

After a resident called 911, deputies spotted Thompson lying in a yard with one hand concealed from view and were concerned that he may be connected to the carjacking suspect, the statement said.

Thompson was initially unresponsive to numerous commands then stood and charged deputies, prompting one who believed Thompson was armed to fire at him, the statement said.

The investigation has included gunshot residue testing, DNA testing to determine if Thompson had been in the carjacked vehicle, interviews with witnesses, deputies and family members, and fingerprinting, the department said.

"We have determined that there is no evidence that Mr. Thompson was in the carjacked vehicle, nor that he was involved in the assault on the deputies," the statement said.

Dawn Modkins, a spokeswoman for Black Lives Matter Long Beach, described Thompson as having diminished mental capacity and being extremely quiet, reserved and non-confrontational.

She said the family believes he was lying down because he was likely scared. She doubts the Sheriff's Department's assertion that he charged deputies.

"He probably saw them coming and he just laid down," Modkins said.

The family planned to demand answers Tuesday from the Los Angeles County Board of Supervisors. They want an answer from the board on how it's going to hold the sheriff accountable, she said.

"They want public apologies. They want an apology for criminalizing him, for devaluing him before they knew who he was," Modkins said.

The deputy who fired at Thompson has been reassigned to duties not in the field.

The department said an administrative review of the case was continuing and the investigation file will ultimately be turned over to the county district attorney for review.