DENVER - Denver police took a man into custody late Monday morning following an extensive search for a suspected gunman inside the Petroleum Building on the 16th Street Mall at Cleveland Place.

Officers said they were initially looking for a man named Robert Jackson.

Police said Jackson was a suspect in a domestic violence case out of Aurora and had felony warrants for robbery and escape out of Centennial.

"We were told he may be armed and dangerous," said police department spokesman Sonny Jackson.

Sonny Jackson said officers made verbal contact with a man they thought was Robert Jackson and that the man fled into the building and hid.

"He actually hid in the ceiling area," Sonny Jackson said.

The Metro Swat Team went from floor to floor searching for the suspect.

"They evacuated some tenants and told others to lock themselves behind closed doors," Sonny Jackson said.

"It was scary," said Ernestine Garcia, one of the evacuees. "They [officers] were all in masks, all covered up, so it's kind of frightening."

Police told 7NEWS that the man who fled into the building tried to sneak out with some of the evacuees.

"Officers spotted him and grabbed him," Jackson said.

The suspect was placed in a squad car and taken to District 6 for further questioning.

It turns out he is not the same man wanted by by Centennial and Aurora police.

After questioning the suspect and checking fingerprints, police identified him as Joseph Smith, 21, of Denver.

"Smith is being held on multiple charges," said Department spokeswoman Raquel Lopez.

"He's been in trouble with the law before," Jackson added. "He does have an ankle bracelet on."

Police say it does not appear that Smith was armed when he entered the Petroleum Building.

They said they needed to find out why he fled from police when they tried to make contact with him.

Police cordoned the sidewalks adjacent to the building and shut down traffic on Broadway and the 16th Street Mall while they searched the building.