Ten years after 20-year-old Calvin Riley was shot dead while playing Pokémon Go on the Aquatic Park promenade, the FBI has posted a $25,000 reward and released fresh detail about two cars — and a bystander recording video — it says were at the scene.

Riley's killing on the night of Aug. 6, 2016 was one of San Francisco's most widely circulated unsolved homicides, a random-seeming shooting of a college baseball player in a tourist stretch of the northern waterfront. A decade later it remains open, and the FBI's renewed appeal is notable less for the reward than for the investigative detail attached to it: the FBI says two vehicles arrived and left the area together, and that at least one person on scene was recording video. It is a rare public window into what the Bureau says it is still trying to learn.

On the night of Aug. 6, 2016, Calvin Riley and a friend were walking near the end of the Aquatic Park promenade — the curved seawall path below Ghirardelli Square that draws joggers, tourists and, that summer, crowds chasing Pokémon Go creatures on their phones. At about 9:50 p.m., according to the FBI, Riley was struck by a single bullet traveling on a north-to-northwest trajectory. He was 20 years old, a former pitcher at Junipero Serra High School in San Mateo who was playing baseball at Delta College in Stockton.

Nobody has ever been charged. On Aug. 6 this year — the tenth anniversary — the FBI's San Francisco Field Office and its national @FBIMostWanted account renewed the call for tips and attached a reward "of up to $25,000 for information leading to the identification and probable cause to arrest" whoever killed Riley.

What distinguishes this appeal from a routine anniversary notice is the specificity of what the Bureau chose to release. Investigators say two people were identified as being in the area at the time of the shooting. The first, described as "Individual One," is believed to have been driving a vehicle parked nearby and was with a blonde woman roughly 20 to 30 years old. A second person, "Individual Two," was seen recording video at the scene.

The FBI also named two vehicles it classified as suspicious: a 2015 white Hyundai Sonata and a dark-colored Audi A3 wagon. The FBI says the two cars arrived together shortly before the shooting and departed together immediately after it.

The descriptions the FBI released this month are of witnesses and vehicles, not a named suspect. The Bureau says it has not identified the two "individuals," and it is asking the public to help trace the cars and locate video from the scene. The renewed reward underscores that the case's most promising leads, in the FBI's telling, still sit with members of the public who have not come forward.

For San Francisco, the killing has never fully receded. Riley was playing Pokémon Go — the augmented-reality game that was a cultural phenomenon in the summer of 2016 — at the moment he was shot, and his death became one of the most-cited examples of the craze's real-world dangers. The Aquatic Park promenade where he was killed remains a heavily used public space, steps from one of the busiest tourist corridors in the region.

The FBI asks anyone with information — including anyone who recognizes the two vehicles or the people described, or who has video from Aquatic Park that night — to contact its San Francisco Field Office at 415-553-7400. A decade on, the Bureau's message this month is that it believes the answer is still out there, held by someone who was on that promenade.