Let suppose following situation:
There is a company private/internal telephone network. The network has got a special feature, that a private telephone call between two office workers can be monitored by a supervisor/manager. That said supervisor can also interfere into the call in a way that he can say something into a microphone that will be heard by both office workers.
What would be the best matching word choice for the given situation?
<...> into private call took place on Monday at 01:15 PM o'clock.
(The preposition 'into' could be of course replaced or removed depending on proper grammar collocation)
Already found: interference or intrusion does not sound good because of subjective opinion. (Has got a pejorative expression)
To clarify, we can suppose that so called manager is already listening the call (this process is already named as monitoring). I'm going to find a word describing an event when he starts to say something.
I also prefer words from formal language (not any slang).