Police searched Wednesday for a 70-year-old man suspected in an office shooting that left one dead and two wounded in Arizona's largest city, saying he is "armed and dangerous."

As police searched for the shooter, SWAT teams and two armored vehicles surrounded his house about 7 miles (11 kilometers) from the shooting scene in Phoenix. Police served a search warrant to enter the home.

For a time, officers, believing the shooter was inside, used a megaphone to ask him to surrender.

The gunfire at the office complex prompted terrified workers to lock the doors to their offices and hide far from the windows. SWAT officers searched the building.

America's latest public shooting came on the same day Congress took up the issue of gun control for the first time since the Connecticut school shooting in December left 20 young children dead and changed the national conversation on guns.

Former Arizona Rep. Gabrielle Giffords, who was shot in the head during a 2011 shooting rampage in Tucson that left 6 people dead, appeared in Washington to testify in favor of stricter gun controls.

Police identified the suspect in the Phoenix office shooting as Arthur D. Harmon. They identified a man who died hours after the Wednesday morning shooting as 48-year-old Steve Singer. He's the CEO of Fusion Contract Centers Inc.

Police say a 43-year-old man was listed in critical condition along with a 32-year-old woman.

Police didn't release the names of the wounded, but a Phoenix law firm, Osborn Maledon, said one of its lawyers, Mark Hummels, was among the wounded.

The firm said he "was representing a client in a mediation" when he was shot.

Around 10:30 a.m., the gunman arrived at the office building and got into a dispute with someone, a conflict that escalated to the point where he drew a gun and shot three people, police Sgt. Tommy Thompson said.

"Everyone was just scared, honestly, just scared," said Navika Sood, assistant director of nursing at First at Home Health Services who along with her co-workers locked the entrances to their office.

Sood said police evacuated the office about 30 minutes after she first heard the popping noises.

Vannessa Brogan, who works in sales support at an insurance business in the three-story complex, said she heard a loud bang that she thought at first was from somebody working in or near the building.

She said others at the business thought they heard multiple loud noises. She said people locked themselves in offices until authorities evacuated the complex that houses insurance, medical and law offices.

Becky Neher, who works for a title company in the building, said the two gunshots she heard sounded like two pieces of metal banging against each other.

Watching from her second-story office, she saw people leaving the building.

"Someone yelled, `We have a shooter,'" she said. She saw two victims lying on the ground outside the back side of the building. She said health care workers who have offices in the complex came out to help.

Don Jaksa, a software consultant who works in the building, said he was listening to the radio when he suddenly heard "two pops." He said he didn't think they were gunshots.

"My co-worker goes to the range all the time," he said. "He identified it as gunfire."

His co-worker then locked the door. After five minutes, they left and ran into police and someone carrying a stretcher. The police escorted them back to their office and told them to lock the door again.

They were eventually evacuated, and as he sat on a rock outside the complex, his wife called to make sure he was OK after seeing the shooting on the news.

Workers were later allowed to leave the building. Two hugged each other when they got outside.

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Associated Press Writers Paul Davenport, Felicia Fonseca and Terry Tang contributed to this report.