They reached the street, to hear the sound of a police siren.

In the background she heard the sound of police sirens.

The sound of a police siren could just be heard in the distance.

From the distance came the sound of a police siren.

In the distance they all heard the police sirens coming.

They could hear the sounds of police sirens in the distance.

He was afraid he'd hear police sirens in the distance at any moment.

Then a police siren and a fire engine at the same time.

The police siren sounded as if it was almost on top of them.

And above it all, the sound of approaching police sirens.