Jake thinks Henry Camerero could be the killer they are looking for but his supervisor doesn't agree, accusing him of bearing a grudge because he couldn't pin down Camerero for a previous murder. When Jake asks Larsen to tail Camerero, against the supervisor's orders, they get into a good old-fashioned shouting match in the parking lot at the Hall Of Justice.
Then ... But Larsen relents and Jake takes him to the Financial District where Camerero works, to point him out.
... and Now, this is One Embarcadero Center, newly completed shortly before the movie was filmed - three similar high-rise office buildings were added to the Center over the following years. This view is from the corner of Sacramento and Front (map). (Incidentally, One Embarcadero also appeared several times in the 1974 movie The Conversation).
Then ... The camera pans down to show them walking west along Sacramento towards the building's south entrance.
... and Now, the entrance awning has been redesigned, retail stores have replaced the alcoves at right and several new buildings have since been built across and down the street.
Then ... They enter from Sacramento Street through an arcade-like tunnel, an architectural feature referred to as a 'people-scoop'.
... and Now, for some reason the tunnels have been removed. Across the street the site of Kielty and Dayton Stationery, on the right above, has been claimed by the 353 Sacramento office building.
Then ... A balcony alongside the footbridge spanning Clay Street at the north side of One Embarcadero (map) proves to be a good vantage point to look out for Camerero - his real estate investment office is in this building.
... and Now, a sign advertises a Landmark Theaters cinema that has since been opened at the Center.
They watch as Camerero, flanked by two colleagues, approaches the Battery Street junction on Clay. From now on he's a marked man.