Those friends painted a very different picture of the man than what had been publicized. Police said he was armed with a knife while trying to steal a bicycle from another man.
On Monday night, Police Chief Greg Suhr held a town hall meeting to give the police version of what happened and to answer questions.
But Chief Suhr and the department's top brass was met by a contentious crowd of hundreds. Many came to defend the man killed by officers.
"He's coming from a poor country, a third world country, and they kill him in front of his house because he had a knife," said one woman who spoke in front of the crowd.
At one point, the crowd chanted, "Shame on you! Shame on you!"
The crowd filled the auditorium of Cesar Chavez Elementary School in the Mission, just blocks from where police shot and killed 21-year-old Amilcar Perez-Lopez.
"It's not fair. What's up with you guys? You're supposed to protect the people. What are you doing? You're doing the opposite," said a fifth-grade boy who was among those speaking out against police killings.
The audience frequently interrupted Chief Suhr as he gave the police perspective of the incident. Suhr said two plainclothes officers were the first on the scene, responding to a 911 call of one man with a knife chasing another man.
"The officers were approximately five to six feet away when the suspect charged at the officers with a knife raised over head. Both officers discharged their firearm," said Chief Suhr.
During last Thursday night's deadly shooting at 24th and Folsom Streets, the chief said the officers fired a total of six shots, killing the man with the knife.
Police displayed a photo of the knife they said the man used.
"The police tactic is to immediately blame the victim. Blame whoever they shot. Demonize that person," said Frank Lara with the ANSWER Coalition, which helped to organize a press conference outside the school before the community meeting started.
Friends, neighbors and co-workers of Perez-Lopez say he was no thief. They say he didn't speak English and likely didn't know the plainclothes officers were police.
"[It's] frustrating. A lot of anger. I didn't want to believe it," said Fernando Quinoez, a friend of Perez-Lopez.
Kevin Born of Ashbury Contruction tells KTVU Perez-Lopez had been working for him for the past two and half years as a radiant heat installer.
"He's a hardworking guy. He wasn't involved in drugs. He wasn't a criminal," said Born. "My big question is how did it happen?"
Supporters say the bicyclist had stolen Perez-Lopez's cell phone and that Perez-Lopez was chasing after him to try to get his cell phone back.
Some chanted, "April 14th! Shut it down! April 14th! Shut it down!" The crowd was referring to a day of action supporters are calling for to protest police killings.
Friends of Perez-Lopez said the priority now is to raise enough money to return his body back to his family in Guatemala.