Alameda County Sheriff's deputies used a full-body restraint device and a spit mask on an inmate they were escorting to the outpatient housing unit in Santa Rita Jail last year, which caused his death by asphyxiation, according to a report by the Alameda County District Attorney's Office clearing the deputies of criminal charges.

The district attorney's investigation into the death of Dujuan Armstrong was concluded on June 24, one year and one day after Armstrong died on June 23, 2018. The report provides the first detailed account of how Armstrong died after his family has spent a year trying to get answers from the sheriff's office. Armstrong's mother Barbara Doss even confronted Sheriff Gregory Ahern in Sacramento in January.

The report contradicts statements by the sheriff's office. An early account from spokesman Sgt. Ray Kelly indicated that Armstrong got into a confrontation with sheriff's deputies while still being admitted to the jail on the evening of June 22, 2018. But the report reveals that the confrontation actually didn't occur until nearly 24 hours later. In a letter to the Board of Supervisors the day after Armstrong died, Ahern wrote that his death was "believed to be the result of a drug overdose."

An autopsy revealed that Armstrong died of mechanical asphyxia induced by a combination of factors including the deputies use of a spit mask and a restraint device called the WRAP, according to the district attorney's report. Dr. Michael Frenec of the sheriff's Coroner's Bureau found that the WRAP, which is wrapped around a suspect's whole body and then pulls them into a sitting position, had compressed Armstrong's overweight stomach and pulled his neck down. The spit mask also prevented him from breathing properly, Frenec found.

The morning after he entered the jail, Armstrong told deputies he had taken drugs before his arrival. His behavior grew increasingly bizarre throughout the day until the deputies decided to take him to the jail's clinic. But on their way, Armstrong fought with the deputies, who restrained him. While the autopsy found some evidence of cocaine and marijuana use, it was not enough to be fatal and did not explain his bizarre behavior.

Asked to clarify the discrepancies, Kelly wrote in an email, "The letter to the board for a custody death incident is a notification. It contains preliminary investigative observations and information. Mr. Armstrong told deputies he ingested drugs and was high. Obviously a lot of fact-finding went on after that letter was written.

"I put out the information I was given at the time," Kelly said of his own statement. "I believe the comprehensive DA report is much more accurate."

Armstrong, 23, was the father of two children and had recently discovered that his girlfriend was pregnant. He worked as a tow truck driver and lived with his mother in Oakland. In May 2018, he was convicted of a burglary that had occurred in 2014. A judge allowed him to serve his 120-day sentence only on the weekends.

He arrived for his second weekend in jail on June 22. He was searched and answered a series of medical screening questions and cleared to enter the jail. He was placed in a cell with other inmates while awaiting medical screening.

One deputy, Alexander Valentine, started his shift at 5 a.m. and wrote in his report that he heard Armstrong yelling in his cell, "Help me!" At 6 a.m., Armstrong flagged Deputy Khalif Hoodye and told him he was high. According to Hoodye's report, he asked Armstrong if he wanted a nurse to evaluate him, but Armstrong said, "Nah, I'm good, I'm good." Hoodye moved Armstrong to a cell by himself and gave him a bag lunch, according to his report.

Valentine wrote that while Armstrong was in that cell, his behavior continued to deteriorate. He was on all fours, barking, crying, and continuing to yell, "Help me!" He banged on the door, which bothered the nurses at a nearby nursing station, so he was moved to a different cell.

While in that cell, Armstrong took off all his clothes. One deputy saw him there naked and asked him to put his clothes back on, but Armstrong didn't respond. Multiple deputies reported that he made no sense when he talked and was often unresponsive and simply stared at the wall. At one point he put his face in the toilet and the deputies shut off the water to his cell.

At around 3 p.m. two nurses took his vital signs and cleared him for further incarceration, despite his bizarre behavior. Valentine also referred him to behavioral health workers, who said that his demeanor was not caused by a mental disorder. Nurses returned to check his vitals at 4:15 p.m., but he banged on the cell door and told them to leave him alone.

At about 5 p.m., Sgt. Anthony Moschetti told deputies that Armstrong had to be taken to the jail's outpatient housing unit for further monitoring. About an hour later Deputies Joshua Plosser, Eduardo Rivera Velazquez, and Kevin Calhoun took him out of the cell, handcuffed him and started escorting him there. Armstrong tried to pull away several times, and eventually they pushed him against a wall and then to the ground, according to the district attorney's report. While on the ground, Calhoun and Rivera-Velasquez kicked and kneed him, the report said. More deputies arrived and put him in leg irons. When he continued to struggle, they put him in the WRAP and spit mask, although the report makes no mention of him spitting.

Once Armstrong was in the WRAP, deputies placed him on a gurney and wheeled him into the outpatient housing unit. The deputies could not tell if he was breathing because of the spit mask. Once they arrived at the outpatient unit, a nurse checked his blood pressure, but then couldn't find a pulse. They removed the WRAP and resuscitated him briefly. He was taken to Valley Care Medical Center, where he died at 7:24 p.m.

While no deputies will face criminal charges, Alameda County will likely be sued over Armstrong's death. Civil rights attorney John Burris filed a claim against the county in December.

The circumstances surrounding Armstrong's death are similar to those of Martin Harrison's in 2010, who exhibited increasingly bizarre behavior while suffering alcohol withdrawal and was killed in a fight with deputies. Harrison's family eventually reached an $8.3 million settlement to be paid by both the county and the jail's for-profit medical provider at the time, Corizon. A year later, the county Board of Supervisors voted to change medical providers to the current one, which became Wellpath after merging with another company last year. Wellpath also has faced allegations of poor health care.

The Ella Baker Center for Human Rights has protested Armstrong's death over the last year as part of its push for a comprehensive audit of the sheriff's office.

Jose Bernal, an organizer with the Ella Baker Center, called for the release of body camera video of the incident and said that Armstrong's family has been "severely tormented" by the lack of answers about his death.

"The immense lack of transparency from ACSO and the DA has only added insult to injury," Bernal wrote in an email. Of the 66 video clips of the incident reviewed by the district attorney's office, Bernal wrote, "So far, it appears as only the sheriff and the DA's office have had any access to these videos. Dujuan's family has yet to see any one of them. This is unacceptable."