"It is we whose" vs "It is us whose"

Question

I'm a bit confused about writing the correct sentence:

• It is we whose flat was robbed.
• It is us whose flat was robbed.

The context is this, A family was robbed and they are in a police department waiting when the police officer calls, "Who's here about the robbery?"

What bothers me is that both sound okay with whose but I somehow feel that "we" is incorrect although it corresponds to "whose" much better than "us".

1. It is we whose flat was robbed. - We are the family whose flat was robbed.

Here are examples from google search:

• Or maybe it's we whose lives are impoverished. Before we parted ways, Philip told me he'd very much like to have a wife just like me someday ... (Source)
• It's we whose eyes can fill with tears, We yet can be aggrieved. We're prone to all our human fears; It's we who feel bereaved. (Source)
• It's we, whose destiny it is to serve others, who are There were shouts, a confusion of commands and of hands of their filthy wishes. (Source)
• But it's we whose meager earnings are at stake that get caught. I call it an outrage." Miss White snapped on the radio, tuned in on Babson's reports, and went on: ... (Source)

and

2. It is us whose flat was robbed. - It is us, the family, whose flat was robbed.

Here are examples from google search:

• “Our guys know that going over there it's us whose back is up against the wall because I give Westfield a lot of the advantages..." (Source)
• It's us that he 'walks with purpose' towards and it's us whose senses he 'overwhelms with his passion'. Ergo, the many thousands of female authors with... (Source)
• It's us whose freedoms are at risk. And it's MPs who retire on a generous, safe pension. Most politicians are not venal - and we need them. (Source)

I'm unsure whether a comma is needed after "it's we/us"!

Edit: In all your duplicates it's who/whom which does differ from whose. Not one of your duplicates explains the pronoun to use with "whose".

Answer 1

From Woe is I: The Grammarphobe's Guide to Better English in Plain English(Third Edition) by Patricia T. O'Conner (Penguin Books, Ltd., 2009):

These days, anyone who says “It is I” sounds like a stuffed shirt. It wasn’t always so. In bygone days, you might have had your knuckles rapped for saying “It’s me” instead of “It is I.” Your crime? A pronoun following the verb to be, the English teacher insisted, should act like a subject (I, he, she, they) and not an object (me, him, her, them). But language is a living thing, always evolving, and It is I is just about extinct. In all but the most formal writing, some of the fussiest grammarians accept It’s me. Most of us find the old usage awkward, though I must admit that I still use “This is she” when someone asks for me on the phone. Old habits die harder than old rules.

Next time you identify the perp in a police lineup, feel free to point dramatically and say, “That’s him, Officer!”

ibid.:

TOMBSTONE: Use It is I, not It is me.

R.I.P. Here’s another ordinance that’s out-of-date. In all but the most formal circumstances, it’s OK to use It is me, That’s him, It’s her, and similar constructions, instead of the technically correct but stuffier It is I, That’s he, and It’s she. Similarly, it’s fine to say Me too. The alternative, I too, is still grammatically correct, but unless you’re addressing the Supreme Court or the Philological Society, you can drop the formality.

My mother was an English professor, so while I never got my knuckles rapped, I certainly got "the look," at which all brave children quail.

All that said, I wouldn't use either one in this context, personally:

Who's here about the robbery? We are. We're the ones whose flat was robbed.

However, if I changed the context a bit, I'd choose us over we:

Why are you talking to them? It's us whose flat was robbed.

Nevertheless, while it sounds better in this context, I'd still probably say We're the ones whose flat was robbed.