Anne was awake too.

She had seen the figure and lay quite still watching it.

Grace silently returned the pressure; then the two lay watching the man's stealthy motions for a moment, while Grace's mind was busy devising a plan by which the robber might be caught.
Oakdale was a quiet, prosperous place, and burglars were unusual.
Occasionally the hands in the silk mills made a disturbance, and there had been a few highway robberies, but an actual house-breaker seldom troubled the law-abiding town.

The two girls, as they lay watching him from under the covers, guessed that this man was a real burglar.

He wore a black soft hat and carried a small electric lantern, while, with a practised hand, he picked the lock of a small drawer in the dressing table where the girls had put their purses.