Arizona Office Shooting Update: Police still searching for alleged gunman Arthur Harmon

(CBS/AP) PHOENIX - Authorities on Thursday are still trying to find the gunman who allegedly opened fire at a Phoenix office complex yesterday, killing one person and wounding two others.

Police described 70-year-old Arthur Harmon as "armed and dangerous." They said Harmon opened fire at the end of a mediation session Wednesday morning at a three-story office complex in north-central Phoenix.

Steve Singer, 48, died hours after the shooting. Police said a 43-year-old man was listed in critical condition and a 32-year-old woman suffered non-life threatening injuries.

"We believe the two men were the targets. It was not a random shooting," said Sgt. Tommy Thompson, a Phoenix police spokesman.

Thompson said the gunman arrived at the office building about 10:30 a.m. and got into a dispute with someone. It was a conflict that escalated to the point where the suspect drew a gun and shot three people.

Police believe Harmon acted alone and fled the scene in a car.

Authorities said Harmon also shot at someone who tried to follow him after the shooting in an attempt to get his license plate number.

According to court documents, Harmon was scheduled to go to a law office in the same building where the shooting took place for a settlement conference in a lawsuit he filed in April 2012 against Scottsdale-based Fusion Contact Centers LLC, where Singer was the CEO.

The company hired him to refurbish office cubicles at two call centers in California, but a contract dispute arose.

Fusion said Harmon was paid nearly $30,000 under the $47,000 contract. But the company asked him to repay much of the money when it discovered that the cubicles could not be refurbished, according to the documents.

Harmon argued Fusion hung him out to dry by telling him to remove and store 206 "worthless" work stations after the mix-up was discovered. Harmon said Fusion then told him that the company decided to use a competitor.

Harmon's lawsuit sought payment for the remainder of the contract, $20,000 in damages and reimbursement for storage fees and legal costs. Hummels was representing Fusion in the lawsuit.

As police searched for the shooter, SWAT teams and two armored vehicles surrounded a home about 7 miles north of the shooting scene. Police served a search warrant to enter the house.

Complete coverage of the Arizona office shooting on Crimesider