PORTLAND, Ore. (KOIN) — Thirteen years after his disappearance, the Multnomah County Sheriff’s Office is still searching for Kyron Horman.

Horman was last seen on June 4, 2010, at Skyline School in Portland, attending the school’s science fair. He was just seven years old at the time of his disappearance.

When Horman vanished, it was treated as a missing person case for nine days before authorities announced it was a criminal case on the 10th day.

The search for Horman sparked one of the largest investigations in Oregon history. No one has been arrested in the case, and there has been no sign of Horman since.

Authorities say that Horman was wearing a black CSI t-shirt with green lettering, black cargo pants and black Sketchers with orange trim. He was also possibly wearing glasses.

Horman has brown hair, blue eyes and a v-shaped birthmark on his forehead. The case and investigation remain open and active.

“Kyron’s disappearance continues to have a profound impact on our community,” said the Multnomah County Sheriff’s Office. “Investigators are using advances in software, digital forensics, and geospatial technology to support and advance their work. In collaboration with our Major Crimes Team partners, the Multnomah County District Attorney’s Office and the FBI, detectives are pursuing all legitimate investigative leads and will continue to do so until Kyron is located.

A $50,000 reward is being offered for information that leads to the resolution of Hormans’s disappearance, according to officials. People can call the MCSO TipLine at 503-988-0560, email MCSOTipLine@mcso.us or contact the National Center for Missing and Exploited Children TipLine at 1-800-THE-LOST or provide an online tip at the organization’s CyberTipLine.