Lois Ellen, who has lived across the street from the Harmon home for about eight years, said she was startled to see all the police cars in the neighborhood.
She said she never met Arthur Harmon but had seen him walking a dog before.
Ellen said he wasn't very neighborly and the people in the Harmon home "keep to themselves."
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.
"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.
Vanessa 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."
The shooting took place on the same day that hearings on legislation to address gun violence were convened in Washington, with former Rep. Gabrielle Giffords testifying for stricter gun controls.
A gunman shot Giffords in the head during a shooting rampage in Tucson in January 2011.
Associated Press writers Paul Davenport, Felicia Fonseca, Terry Tang and Walter Berry contributed to this report.