The D.C. medical examiner’s office has ruled the death of a man found handcuffed and not breathing on Nov. 1 a homicide. 27-year-old Alonzo Smith was in the custody of armed security guards at a Southeast Washington apartment building. (WUSA 9)

The D.C. medical examiner’s office has ruled the death of a 27-year-old man a homicide after he was found last month unconscious and handcuffed in the custody of armed security guards at a Southeast Washington apartment building.

LaShon Beamon, a spokeswoman for the D.C. Office of the Chief Medical Examiner, said Alonzo Smith, a schoolteacher, died of “sudden cardiac arrest” complicated by “acute cocaine toxicity while restrained.” She listed a secondary cause of death as compression.

Justin Dillon, a former federal prosecutor in the District, had not seen the autopsy report but said such a ruling means that the medical examiner “apparently determined that compressions of his torso due to restraints was a contributing factor to his death from too much cocaine.”

Smith’s mother, Beverly Smith of the Woodland neighborhood, said she agreed with the homicide ruling but questioned the determination that her son had used drugs. “Cocaine had nothing to do with my son’s death,” Smith said. “That’s why they ruled it a homicide.”

Smith said she believes that her son was beaten or suffered some other type of trauma at the hands of the security guards. “My son gave no indication that he was a cocaine user,” she said, adding that the drug finding “does not negate the fact that the autopsy report stated that it was a homicide, which indicates something was done to him.”

Alonzo Smith was a schoolteacher and father. (Family photo)

She said blaming drugs in part for her son’s death “just validates my suspicion that they are trying to cover up something.”

The homicide ruling does not necessarily mean that a crime has been committed. It means the medical examiner concluded that Smith died at the hands of another. It will be up to D.C. police and prosecutors to decide whether there was criminal intent.

D.C. police did not respond to requests for comment on the investigation. The U.S. attorney’s office said it is investigating. Smith’s mother said police told her that a grand jury had been convened. Bill Miller, a spokesman for the U.S. attorney’s office, said he could not comment.

The guards, who have not been identified, are known as “special police” and are armed, have arrest powers and are licensed by the District. They are employed by Blackout Investigations, which is run by a retired Maryland State Police sergeant. Company officials did not return calls seeking comment.

Smith was found unable to breathe and in handcuffs Nov. 1 in a second-floor hallway of the Marbury Plaza apartments in the 2300 block of Good Hope Road SE, according to a D.C. police report. District officers responding to a call about an assault discovered Smith.

Police accounts do not provide details about what happened before D.C. officers responded to the encounter between Smith and security guards at about 4 a.m. A report says Smith was ­unconscious and in handcuffs when D.C. officers first saw him. The report says officers administered CPR before Smith was rushed to United Medical Center, where he died.

Smith’s uncle, Derrick Knight, 49, has said relatives heard from D.C. police and residents that Smith was visiting the complex possibly to see a woman and that the two may have had a dispute. Knight said residents told him that, at some point, Smith ran down a hall calling for help and shouting, “They’re trying to kill me” as he banged on doors.

Authorities declined to make the autopsy report public but gave a copy to Smith’s mother, who allowed The Washington Post to review it. The autopsy lists internal hemorrhaging to the right side of Smith’s neck and at the C2 vertebrae in his neck, contusions on his chest, hemorrhaging in areas of his upper and lower back, and abrasions on his torso, shoulders and arms. The report does not explain any references to his being restrained or the potential effects of drugs or blunt-force trauma in connection with the cause or manner of his death.

Smith was a resident of Southeast Washington and the father of a 6-year-old boy. He had worked since 2012 at the private Accotink Academy Learning Center in Springfield, Va., which teaches students with emotional and learning disabilities.

District authorities are asking anyone with information about this case to call D.C. police at 202-727-9099.

Perry Stein contributed to this report.