PORTLAND, Ore. (KOIN) – A man accused of planning a “violent attack” at an Oregon climbing event last weekend appeared in Deschutes County court Friday.

The Deschutes County Sheriff’s Office says it worked with Portland police to investigate 39-year-old Samson Garner – who now faces several charges, including attempted murder.

Garner was arrested for allegedly planning to shoot and kill attendants at the three-day Smith Rock Craggin Classic climbing festival. He now faces four counts of attempted murder, eight counts of attempted assault and 15 counts of unlawful use of a weapon.

His motive remains unclear, as many of these court documents are sealed. However, authorities and event organizers say if this plan hadn’t been stopped, the event that hosts hundreds of people could have been deadly.

Deschutes deputies received a tip from Portland police on Oct. 16 that Garner was planning a violent attack, and another tip three days later that he was on the move. In response, a SWAT unit spotted Garner in his vehicle and took him into custody – just one day before the start of the festival.

Investigators who searched his car say they found evidence of a planned attack, including a Beretta 9mm handgun, a Sig Sauer 9mm handgun, an AR-15 rifle, and an HG1.

A charging document also outlined Garner’s alleged targets, who were written as belayer one and two and spectator one and two.

Event organizers say authorities warned them of the threat on Wednesday ahead of the festival. They then partnered with law enforcement to notify attendees, vendors, and volunteers of the investigation and Garner’s arrest.