Collocations for robber - noun

armed, masked (esp. BrE)
bank, train
grave, tomb
highway
would-be (esp. BrE)
The would-be robber fled empty-handed.

band, gang

chase, hunt (BrE), search for
Police are searching for the robbers.

catch

hold sb/sth up
Robbers held up a bank at gunpoint.

snatch sth (esp. BrE), steal sth, take sth
escape with sth, get away with sth, make off with sth
Robbers escaped with $30 000.