Complex sentence: The murder took place in the "Greyhound" public house (popularly known as "The Spotted Dog"), High Street; this is now a private building called Buckingham House and it bears a commemorative plaque to mark the event.
Split into simpler sentences: The murder took place in the "Greyhound" (popularly known as "The Spotted Dog") on High Street. Now a private building called Buckingham House, it bears a commemorative plaque marking the event.