Pease, 47, was not hurt, but "he was somewhat shaken up,'' said Arlington County police spokesman Ken Rosenberg.
The freshman congressman was walking away from the Crystal City Metro station at about 8 p.m., when a gunman ordered him to give up an undisclosed amount of money, Rosenberg said.
Pease flagged down an officer, who with other detectives chased the suspect and arrested him.
"They recovered both the money and the weapon," Rosenberg said.
The suspect was not identified. Rosenberg said charges were pending.
Pease, of Terre Haute, Ind., was first elected to Congress in 1996.
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