In a total war we have to keep people under constant surveillance.

He was kept under surveillance until his death in 1941.

I kept him under surveillance, but he caused no trouble at all.

I kept his car under surveillance, waiting for him to return.

We'll have to keep you under surveillance outside of the school.

I'll keep the area under surveillance and see who comes back to the spot.

And we are trying to do something other than keeping you under close medical surveillance.

We will then make it our business to keep you under constant surveillance.

The Bureau should do everything to keep them under surveillance.

He was kept under surveillance for several months before being arrested in March.