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When Leah Costa appeared on Monday morning’s media rounds in the wake of her exit from Bachelor in Paradise, something stood out.

A very conspicuous, very conversation-worthy engagement ring.

You see, when Leah walked out of Bachelor in Paradise just a few short months ago, she was decidedly not engaged. She also wasn't, to our knowledge, in a relationship, given that she was lamenting the lack of romantic prospects in Fiji.

So it appears in the time between when the show wrapped up filming, and TODAY, Leah has fallen in love and become engaged.

Obviously, the most pressing question of the day, nay, the week, therefore, is: WHO IS LEAH COSTA ENGAGED TO PLS.

At present, she has dropped the following clues as to who her fiancé is:

1. He lives in Melbourne
2. He is famous/the public know him
3. He isn't from The Bachelor/The Bachelorette

In an interview with Mamamia on Monday, I yelled at asked Leah to please tell us who her fiancé is, thanks, before explaining that I'd gone deep on her Instagram.

Watch Leah dodge questions about her ring on Studio Ten. Post continues after audio.

"You're never going to get it," she said. "I've given you breadcrumbs, [but] I've been quite careful and coy about it."

She did, however, drop one final clue: they've known each other for years.

Being the Spotlight journalist that I am, I therefore decided to do some very serious investigative research, using the most reliable tool I have available to me: Instagram. This is my three part investigation.

Step 1: Who is Leah following who fits this description?

Leah is only following 674 people, and considering I follow most Australian celebrities (for... for work. Just for work), anyone I follow should come up right at the top.

I spot a few names of interest:

Lee Elliott. No he has a girlfriend and was also on The Bachelorette you idiot.

Telv from Married at First Sight. Interesting. Pretty sure he keeps posting about his new girlfriend though, and it's not Leah.

Tommy Little. The Project co-host. Oooooh hello.

Listen to Mamamia's latest episode of Bach Chat, where Michelle Andrews and Zara McDonald recap Bachelor in Paradise. Post continues after audio.

Wais Gavidi. I guess he's sort of linked to The Bachelor, and also I don't feel like Leah has known him for years. Oh, and he probably lives in Fiji, not Melbourne.

Taylor Henderson. Came second on X Factor a few years ago, and might just be random enough for it to be true.

Josh Gibson. Former AFL player who was recently on I'm a Celebrity. Definite possibility.

Jono Pitman. Villain from Married at First Sight season two.

Step 2: Which of these people is ALSO following Leah?

Oh.

So, um, none of these people are following Leah.

That's... that's not how I expected this investigation to go down.

Step 3: Go rogue.

Now it's time to just go where my spidey senses take me.

One direction is Shane Warne. He likes blondes. Lives in Melbourne.

The other is David Witko. Leah has been photographed many times with the ex-Bachelorette villain, and YES I know she said it's no one from the show but maybe that was just to throw us off the scent?

They also don't follow each other on Instagram which seems bizarre given that they're clearly good friends.

Merry Christmas to you all #celebrate #christmas #santa #naughtyornice #merrychristmas

A post shared by Leah Costa (@leahpcosta) on Dec 10, 2017 at 12:03am PST

We also can't rule out the people she's following and aren't following her back, because that could be a ploy, AND there's the possibility that there's somewhere out there following her who she's not following, but I'm way too busy to go through all 35,000 of them.

Being an investigative journalist isn't as fun as I thought it would be.

But luckily, something tells me Leah will be telling the full story to a magazine in no time.