Eighteen-year-old Desiderio "Desi" Romero V went to the party on a whim, his family says, answering an online invitation that had circulated only a couple of hours before the gunfire. Three weeks later, they have buried him with no one under arrest — and with the FBI now offering $20,000 for the tip that could name a shooter.

The July 25 mass shooting at a social-media-promoted gathering in an open field near Morgan Hill — one killed, six wounded, hundreds present — has hardened from a spot-news tragedy into a stubborn unsolved case that has drawn in federal agents. In early August the Santa Clara County Sheriff's Office said the FBI had joined the investigation and posted a reward of up to $20,000. Days later, Romero's relatives gathered at a San Jose church to grieve a teenager whose only apparent misstep was showing up.

Romero, an 18-year-old San Jose resident known to many as "Pepper," was fatally shot and six others were wounded shortly after 10 p.m. on Saturday, July 25, when gunfire tore through a crowd along Hale Avenue near Miramonte Avenue in an unincorporated stretch of Santa Clara County. The gathering had been promoted online — described by KRON4 (external source, opens in a new tab) as a birthday event for a San Jose-based Twitch streamer — and pulled more than 300 people out to a rural property. Romero died of multiple gunshot wounds, the county Medical Examiner's Office found, as San Jose Inside reported (external source, opens in a new tab).

The Dissent covered the shooting itself in late July. What has shifted since is the investigation's trajectory. In its early-August announcement, carried by NBC Bay Area (external source, opens in a new tab), the sheriff's office said the bureau would add federal resources and technical support to a case built around a crowd of witnesses that has yielded no suspect. Sheriff Robert Jonsen has leaned on that math: in a crowd that large, he argued, someone must have seen who opened fire, and he urged anyone holding back to come forward.

The grandfather kept circling back to their goodbye that day — an exchange of "I love you" that he said he would carry for the rest of his life.

The reward amounts to an acknowledgment of how hard the case has proven. The FBI's San Francisco office, through Special Agent in Charge Scott Schelble, said it believes a witness is holding a detail that could push the case forward, and that no tip is too small. The bureau has opened a digital tip line for anyone who filmed or photographed the scene that night, and is fielding calls at 1-800-CALL-FBI. Neither agency has offered a motive.

For the family, the federal escalation has arrived in the middle of raw grief. At a service at Santa Teresa Catholic Church in San Jose, relatives described a killing that turned entirely on chance. The teenager's grandfather, Desiderio Romero III, told NBC Bay Area (external source, opens in a new tab) that the invitation had gone out online only a short time before the shooting, and that his grandson's decision to go had been utterly last-minute.

The grandfather kept circling back to their goodbye that day — an exchange of "I love you" that he said he would carry for the rest of his life. "The words for him to say 'I love you poppy,' or grandpa … I'll never forget," he told the station. Updates from the sheriff, he added, had left him cautiously hopeful an arrest would come, though he would not elaborate for fear of harming the case.

A fundraising page for the family had raised $35,207 by early August, according to San Jose Inside (external source, opens in a new tab). At the memorial, relatives and family friends spoke of a life cut short far too fast, and of the wide circle — siblings, cousins, grandparents — the teenager left behind.

Three weeks out, a sheriff's search-and-rescue team has combed the field near Hale Avenue, the reward is on the table, and the federal government is in the case. The central fact has not moved: no one has been arrested for killing Desi Romero.