The two got into an argument on the front porch of the younger man's home that escalated into an altercation and a struggle over a 9mm handgun the younger man carried in a hip holster, Small said. During the struggle, the older man was shot several times, including twice in the neck, Small said. The victim was pronounced dead at the scene at 4:25.
The gunman had a license to carry a concealed weapon. Police were checking to see if it was still valid.
The younger man stayed at the scene until police arrived and was taken to the Homicide Unit for questioning.
Miguel Rivera, 37, who lives in the neighborhood, said he was walking south on Torresdale when he saw the men arguing and scuffling. Suddenly he heard gunshots.
"He didn't run. He just stood there," Rivera said of the gunman. "I guess he was shocked at what happened."
Rivera described the gunman as 5 feet, 6 inches tall, and he said the victim was about six feet tall and appeared to weigh more than 250 pounds.
The two men had been arguing about the dogs since the middle of last year, Rivera said.
Both men were married with infant children, said Patricia Batista, 58, who lives in the neighborhood.
"It's a shame to take someone's life over that," Batista said, referring to the subject of the dispute.
Contact staff writer Robert Moran at 215-854-5983, bmoran@phillynews.com, or @RobertMoran215 on Twitter.