double cross
noun
a betrayal or swindle of a colleague.
Used to describe an action that was ongoing continuously in the past up until another past event interrupted it.
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Arnold Rivers had been double-crossing Dunmore ... or had Dunmore been double-crossing Rivers?
From Murder in the Gunroom by H. Beam Piper