During night hours the level is set low so security guards can hear any suspicious sound as they tour the office.

Five members of one family fled the building when they heard suspicious sounds.

Brother Narev made a suspicious sound deep in his throat.

Moving on, they paused outside the closed and darkened museum, listening for suspicious sounds.

"Speak for yourself," Gabriel said, already beginning to wonder about some of the suspicious sounds coming from his stomach.

Then he heard the first suspicious sound of the entire night.

As Peter heard no more suspicious sounds they all went on again, very quietly indeed.

And that group hanging around the building before you went in sounds a bit suspicious.

But still nothing showed and no suspicious sound came to their ears.