A zone by zone search of Rose Medical Center Friday evening did not turn up a suspect or any victims after scores of police descended on the campus in response to reports of an active shooter.
Denver police tweeted a little before 10 p.m. that their search of the hospital campus was complete.
Denver police spokesman Tyrone Campbell said earlier Friday evening that police officers would continue to search the campus for "as long as it takes" to make sure every room had been checked.
Police would still like to speak to a person of interest, described as a white man in his mid-30s, around 130 pounds, wearing a flannel shirt and a hat.
Campbell would not say whether there was any evidence of shots ever being fired, such as bullet holes or shell casings.
But as the evening stretched on, it seemed that early reports were mistaken.
"We conducted a zone by zone systematic search of the facility," Campbell said. "We did not locate a suspect or a victim."
That said, "this is an ongoing situation." On Twitter, the department called it "a very active, ongoing investigation."
Employees were allowed to leave the building and go to their cars as each zone was cleared. The hospital reopened around 8 p.m.
Campbell said that the first call came in at 4:17 p.m. and that the police were on the scene three minutes later.
"Right now, we are responding on multiple calls that came into our dispatch center," he said earlier in evening.
"This is a very fluid situation, an ongoing situation, and we are open and ready for however this turns out," he said.
The hospital campus spent several hours on lockdown Friday after the initial reports of shots fired and an "active shooter."
Anna Degraaf, a medical support assistant at the Veterans Affairs Eastern Colorado Health Care building, waited outside while Denver police searched for a suspect.
"I'm concerned just because it's so close to where I work, and I'm concerned because the population of who we treat is very knowledgable about weapons," she said, as she waited to be allowed back to her car, which was inside the area police had blocked off.
George Moloney said his wife was feeling faint on her way home this afternoon and, as they had moved to Denver recently and did not yet have a regular doctor's office, decided to go to the emergency room. She went into Rose Medical Center around 4 p.m. and was there when the building was locked down.
"I feel pretty good about where she is," Moloney said. "I just wish they'd find the guy."
This story has been updated throughout to reflect changing news.
Denverite reporters Adrian Garcia and Ashley Dean contributed to this report.