Alonzo Smith, 27, died Nov. 1, after being found handcuffed by special police officers in an apartment building in Southeast Washington. (Family photo)

IN SEPTEMBER, a 57-year-old man allegedly wielding a knife was fatally shot by a private security guard in Union Station. In October, a 74-year-old patient at MedStar Washington Hospital Center died two days after a clash with private security guards. And last month, a 27-year-old man died after he was restrained by security guards at a Southeast apartment building. It will be up to police and prosecutors to determine if there was criminal culpability in any of the cases, but the fact of these three deaths in three months demands that D.C. officials take a serious look at how they regulate the private police forces that help patrol the city.

The deaths of 57-year-old William Thomas Wilson Jr. , 74-year-old James E. McBride and 27-year-old Alonzo Smith are being investigated by the U.S. Attorney’s Office. Cause of death for Mr. McBride is pending, but police documents obtained by The Post’s Peter Hermann said he suffered a broken vertebra near the base of his neck. Mr. Smith, the medical examiner ruled last week, died of “sudden cardiac arrest” with a contributing factor of “compression of [the] torso.” A video from a camera worn by a D.C. police officer who arrived after Mr. Smith had been handcuffed shows a private security guard with his knee pressed to Mr. Smith’s back. “Not how we train,” said Police Chief Cathy L. Lanier when asked about the tactic. D.C. police have had no in-custody deaths this year; there were two police-involved fatal shootings.

So the inevitable question is whether the training required and received by private security officers is sufficient. According to city officials, there are nearly 17,000 private security officers (special police and general security) affiliated with 122 security companies who staff housing projects, hospitals and other properties in the District. Some carry weapons and can make arrests after undergoing certification by the police department. Training is conducted by a third-party vendor, and D.C. Council member LaRuby May (D-Ward 8) has questioned the rigor, pointedly wondering if the situation would be different “if more predominantly white properties had armed security guards.”

Encouragingly, city officials are taking the concerns seriously, and the administration has promised to review its oversight. Council member Kenyan R. McDuffie (D-Ward 5) has introduced legislation that would increase training requirements. It was also heartening to see Mayor Muriel E. Bowser (D) order release of the video in Mr. Smith’s case. While it doesn’t provide the answers that explain his death, it showed the city’s willingness to share information — something that goes a long way in building public trust.