A 19-year-old who was fatally shot in Crocker-Amazon two months ago appears to have been killed in a revenge attempt by the younger brother of a boy whose brother was murdered in the Mission five years ago.

A 17-year-old suspect, whose name has not been publicized because he is a juvenile, is in custody for the September 8 murder of 19-year-old Luis Quiñonez, who was sitting in a car on the 300 block of Rolph Street with his girlfriend when both of them were shot by an assailant. The girlfriend survived with a gunshot wound to her arm.

That 17-year-old, as the Chronicle is now reporting, was 12 years old when he watched his 14-year-old brother Rashawn Williams get fatally stabbed outside a corner store in the Mission on September 2, 2014. The younger Williams, then 12, and his then-six-year-old brother rode in the car with their brother and mother to SF General while Williams bled to death.

Quiñonez was one of two boys who confronted Williams outside of Rubin’s Market at 26th and Folsom streets, and he was initially arrested for the stabbing. He was exonerated, however, when the SF Public Defender's Office found grainy surveillance video from across the street that appeared to show that the second boy, and not Quiñonez, was the one wielding the knife.

The second teen was reportedly known to police, however he was never arrested or charged for the killing, and a year later he was killed in an unsolved murder in Bernal Heights.

Now both of the teens who were involved in the confrontation that killed young Rashawn Williams are themselves dead, and the Chronicle notes how the story is indicative of "the profound harm of street justice in cities such as San Francisco, with tit-for-tat attacks often cascading for years." Both the Williams and Quiñonez were back in court for a recent hearing, back together and grieving but this time with roles reversed — the Quiñonez family now blaming a Williams sibling for the death of their son. They also, as the Chronicle reports, blame the SFPD for never arresting Williams' real killer, thereby letting the psychological wounds of his death fester and result in another death.

The case echoes the recent talk of connections between the gang-related killing of four young men in Hayes Valley in 2015 and the October 31 house-party killings of five people in Orinda, several of whom had reputed gang ties. One of the men killed was the half brother of the lone suspect in the Page Street shooting four years ago, and was himself tied to the Page Street Mob.

Photo of Luis Quinonez via gunmemorial.org