Police report provides new details about fatal workplace shooting

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By Andrew Michalscheck By Andrew Michalscheck

PHOENIX -- A new police report is shedding light on the details surrounding a fatal workplace shooting that claimed the life of two men.

While Arthur Harmon’s family said he was acting “normal” in the days before the shooting, information gathered by authorities suggests Harmon had been carefully planning to kill businessman Steve Singer and attorney Mark Hummels.

Harmon, Hummels, and Singer met on the morning of Jan. 30 at a business complex near 16th Street and Glendale Avenue for a mediation regarding a legal dispute.

According to police records, Harmon’s wife said that Hummels “had been badgering the family.”

Harmon, however, had been described by the mediator as “stubborn and difficult to deal with.”

Negotiations reportedly broke down on Jan. 30, and Harmon left their meeting and walked out of the building.

Singer’s business partner Peter Claypatch saw Harmon return to the building with a gun, and yelled for everyone to run as fled for safety.

Unfortunately, Claypatch’s warning wasn’t enough to help Hummels and Singer.

The police report said Harmon had two guns, and shot both men until his first gun ran out of bullets. He then used the second firearm to shoot Hummels and Singer execution style.

Harmon was able to escape, but he was found in Mesa the next day dead from a self-inflicted gunshot wound.

Police said Harmon had a handgun in his right hand, as well as two additional firearms in his vehicle.

Harmon also had ammunition, clothes, toiletries, legal documents, and a list of names and addresses.

Police records indicate that detectives followed up with every individual who was on Harmon’s list, and they were all unharmed.

Investigators do not know why Harmon had a list of names, and it’s unlikely that they will ever know now that he is dead.