But Franklin Manuel Santana was new to the block. He, his wife and their newborn daughter moved from Miami to their first-floor apartment on Torresdale Avenue near Magee just a month ago.
So when Santana knocked on Harris' door late Tuesday afternoon to talk about the poo problem, he went unarmed - and unsuspecting.
Frances Fogarty, walking to the ShopRite to get T-bone steaks for Valentine's Day dinner, witnessed what happened next.
"Frank was calm, polite," Fogarty, 45, said yesterday. "He said: 'I'm just asking you, please keep your dog off my lawn. If I have to come back here, there's gonna be a problem.'
"Tyrirk said, 'Oh, is that a threat?' And then Tyrirk just pulled out the gun and shot him in the face. Then he stood over him and let out all the rest of the rounds, maybe nine or 10 more."
Fogarty's boyfriend had tackled her to the sidewalk out of the potential path of any stray bullets. But Fogarty couldn't keep her eyes off the gunman. As Santana sagged lifeless, Harris stalked around the porch for a few seconds.
"He looked around to see if anybody saw him, and then he went back upstairs. That's what I call cold," Fogarty said. Paramedics declared Santana, who would have turned 48 on Saturday, dead at 4:25 p.m. Harris, charged with murder and gun offenses, faces a preliminary hearing Feb. 29.
In a city with countless tales of murder of questionable motive, Santana's slaying stunned even lifelong residents and seasoned cops.
"He lost his life over taking pride in his lawn. A little girl is going to grow up without her daddy over this," said neighbor Jessica Hill, who sat with Santana's wife, Raquel, yesterday as she waited for her husband's relatives to arrive from his native Yonkers, N.Y.
Raquel sobbed as she tried to make sense of something so senseless.
"You got to be careful. You can't just speak to anybody anymore," Raquel said, as 6-week-old Roxxanne slept in a carseat in the family's cozy living room. "[Santana] had no weapons on him. [Harris] had no reason to shoot eight times." But Harris' history suggests he had a temper that was tough to tame.
In November 2004, he was arrested for allegedly punching his girlfriend so hard, he knocked her tooth out, according to court records. A judge issued a stay-away order, but the case ended without conviction when prosecutors withdrew charges for reasons not explained in the court file.
That same year, Harris got a job as a school police officer, working on a per-diem basis. He lost the job last June, when the school district laid off hundreds of employees to save money, a school spokeswoman said. Neighbors believe he has been unemployed since.
Harris had a concealed-carry permit, but it was revoked last January, police said, declining to specify the reason.
His dogs - a Chihuahua and a German shepherd - were a constant bother to neighbors.
"They used to just have the Chihuahua," said Jovetta Streets, who lives in the first-floor apartment under Harris. "But then they got another dog earlier this year, so then it was double-poop on everyone's lawns."
Neighbor David Cheatley, 32, twice talked with Harris about the dog droppings. "Instead of cleaning it up, he'd just make sure to skip my lawn," Cheatley said. Fogarty said Harris and his girlfriend cursed at her when she asked them to clean up after their dogs.
Yesterday, most lawns on either side of Harris' apartment were studded with dog deposits.
Raquel said that she and her husband moved to Philadelphia "for a better life." Santana worked in construction remodeling homes and had hoped to start a business with a friend here. That didn't work out, but the couple decided to stay, and he was lining up other remodeling jobs, she said.
When Raquel heard the gun blasts Tuesday, she ran outside and spotted her husband collapsed near Harris' porch. She sprinted to help but realized within seconds that his wounds were fatal. She called 9-1-1 on the cellphone she fished from her dead husband's pocket.
When officers arrived and led Harris from his apartment in handcuffs, Raquel called out to him, as she crouched beside her husband's body.
" 'I can't believe you did this! I can't believe you did this to me and my family!' " she said she told him. "He just looked at me and didn't say anything at all."