On Jan. 6, just after 8:30 p.m., Robert Dutkevitch rolled his wheelchair onto the smoking patio outside The Argyle assisted-living facility in Denver. Minutes later, the 73-year-old suddenly slumped in his chair, his head lolling to the side.

He then fell headfirst into some rocks, not moving. Another resident outside went in to report what had happened.

Thirteen minutes passed before anyone inside the facility responded and tried to revive him, according to a health department investigation, police records, a 911 transcript, and outdoor surveillance footage obtained by The Denver Gazette.

It is unclear whether Dutkevitch could have been saved.…