PORTLAND, Ore. (AP) — Police have arrested a 19-year-old Portland man in connection with armed robberies that happened during meetings arranged through Facebook Marketplace.

Jarone Walker Jr. is accused of carrying out four robberies using a handgun to threaten seven victims, The Oregonian/OregonLive reported.

Three robberies happened earlier in April, and the first robbery happened Sept. 29. Several of the robberies happened during meetings arranged through Facebook Marketplace to buy or sell property, police said.

Walker was arrested Friday at his home, and booked into the Multnomah County Detention Center.

He is charged with four counts of robbery with a firearm. It wasn’t immediately known if he has a lawyer.

Police are investigating whether Walker was involved in additional robberies.