Legal Question in Criminal Law in Virginia

Re: citizen arrest legal?

Yes, Virginia, as all other U.S. jurisdictions, allows for citizens' arrests but only for felonies and, apparently, not for misdemeanor offenses, a very important exception. (DC is the same.)

The authority for such arrests dervives from the British common law traditions when the Medieval Sheriff of Nottingham (perhaps, being short of deputies?), felt it necessary to involve the common citizenry in the roundup of hooligans and common criminals.

However, these days citizen arrests are rarely advisable for the average citizen to undertake since a standard of strict liability applies, and, if you make a mistake, you could be charged with crime(s) and sued as well in civil court. (On top of that you could get yourself killed or seriously maimed.)

The better course is to call 911 immediately if you become a witness to a crime and let the local constabulary handle it.