The police entered into the building with dogs.
The police entered the building with dogs.
The police went into the building with dogs.
When enter means ‘go into a place’, put the place directly after enter, without in or into: ‘A strange man entered the building.’ ‘As soon as she entered the room, I left.’
We say go into a place, but enter a place.
Enter into has a different meaning and is used in expressions such as enter into an agreement.