The man police were looking for was identified as William Arthur Harmon III, 70, KPHO-TV, Phoenix, reported. Police said they believed Harmon may have had mortgage problems and that the shooting occurred during a mediation session, the TV station said.
Phoenix police said the altercation began about 10:30 a.m. and escalated into multiple shots being fired.
Steve Singer, 48, owner of the Scottsdale call center Fusion Contract Centers, was fatally wounded. Mark Hummels, a 33-year-old lawyer, was hospitalized in critical condition at the hospital and a 32-year-old woman with non-life-threatening wounds, the TV station said.
Three other people were hospitalized for stress brought on by the shooting, the Times reported.
The law firm Osborn Maledon said in a statement Hummels was representing a client in a mediation session when he was shot, KPHO-TV said.
The Times said the gunman had filed a lawsuit against Singer's firm and the law firm was handling the mediation between the two parties.
Witness Larry Ruch told The Arizona Republic an estimated 50 police cars responded to the scene and the balconies of nearby buildings were jammed with onlookers.