Arthur Douglas Harmon (right) is the man Phoenix police are looking for as he's believed to have shot three people and killed one at an office complex yesterday—while the Senate hearing on gun violence carried on in Washington.

There's no doubt that the reason we're paying close attention to yesterday's Phoenix shooting is timing. It not only occurred after former Arizona Congresswoman Gabby Giffords—a victim of a mass shooting in Tucson—spoke and during the exact moment when the country was watching its top officials discuss gun control on TV, but it's also was the third time in two months that a shooting interrupted a public and governmental conversation on guns.  

Yesterday, we were told that the shooting was not a random act of violence and Phoenix police have added bit more detail about the circumstances and the killer's motive. Talking Points Memo's David Taintor reports: 

According to Phoenix police spokesman Sgt. Tommy Thompson, Harmon was in a meeting at the office complex Wednesday morning concerning a legal matter. He got into an argument afterward with two of the people involved, Thompson said, and allegedly shot those two people. One other person was injured in the gunfire, according to Thompson.

According to ABC-15 in Phoenix Arizona, one of the victims died at the hospital, another remains in critical condition, a third has sustained non-life threatening injuries, and two other victims were treated for non gun-shot related injuries. Police say Harmon is still at large.