The two men had been under observation since then, they said.
And he was sure they had him under such observation.
"We can keep her under observation if she is actually living in the house."
He'll stay here for a couple of days under observation.
I will check your wife into the hospital and keep her under close observation.
All of whom have been kept under observation in a hospital.
He will remain in hospital under observation for a short period.
She was moving under observation of someone - or something - else.
For the moment we have their safe house under observation.
Just in case, however, I will be keeping him under observation for another month.
