From this:

Two Chinese diplomats, away from their Los Angeles consulate improperly, recently sped their vehicle past a Los Alamos National Laboratory guard post near classified facilities...

U.S. officials said the incident involving the two diplomats was an intelligence-gathering mission, with the men probably testing Los Alamos security to see how guards react... The diplomats also might have been trying to recover material left by an agent or planning to meet with an agent, the officials said...