Family members say Jackson went by the nickname Kooder. He had been a student at Jefferson High School in Daly City, but the school district's superintendent says he left school this past fall and it's unclear if he was attending anywhere else.
Additional wellness counselors and staff were on hand at Jefferson High School Tuesday. School officials say Jackson has a family member still connected to the school.
RELATED: SF police search for suspect in fatal shooting of teen
"It's a tragic event for young people trying to understand why this happened, why it happened to somebody they know, and why it continues to be happening in our communities, why young people are taking each other's lives," said Superintendent of Schools for the Jefferson Union High School District Dan Burns.
Jackson was driving a white Pontiac near Sunset Boulevard and Kirkham Street Monday around noon when he was shot, possibly by someone in a passing car.
Evidence markers highlighted at least five bullet holes along the side of the car. Jackson died at a nearby hospital, where his family were gathered outside the ER. His 16-year-old passenger was not hurt.
"It doesn't make sense. There's no answers for it," said Burns.
Sunset District neighbors are also at a loss to understand. "Any time that a minor is killed or harmed from gun violence, it's terrible," said Maor Dhari.
San Francisco police have said they are following up on a lead. "There was talk of a mention of a vehicle in the area at that time, so at this time we're going to try to see if there's anything related we can find," said SFPD Spokesperson Officer Giselle Talkoff.
"The staff and students at the school have also asked that we keep this young man and his family in our thoughts and prayers," said Burns.
Jackson's aunt described him as sweet, funny and said that he lit up any room.
RELATED: 15-year-old fatally shot in SF's Sunset District
Anyone with information about the case is encouraged to call the Police Department's anonymous tip line at (415) 575-4444 or to send a tip by text message to TIP411 with "SFPD" in the message.
Superintendent of Schools Dan Burns says Raejohn Jackson's murder is a tragedy, says Raejohn had dropped in the fall pic.twitter.com/Eg8RLHtjWL— Melanie Woodrow (@MelanieWoodrow) May 2, 2017