A man threw hot coffee on the front desk clerk at an Arlington Best Western, jumped over the counter and stole cash from the drawer, police said.
He made off with $450 and a cell phone, then sped away in a white sedan, police said.
It happened at about 9:45 p.m. Tuesday night in the 2400 block of South Glebe Road. A police dog and a U.S. Park Police helicopter helped with the search for the robber, but were unsuccessful.
The suspect was described as a black male weighing 170 pounds who wore a black hat, reading glasses, black athletic jacket, white athletic shorts and white shoes during the robbery.