Was Sofia Richie the reason for Tobey Maguire and Jennifer Meyer's split after nine years of marriage?! That's what we want to know!

Pix have just surfaced of Sofia, 18, and Tobey, 41, looking pretty cozy at 1Oak in LA on Oct. 1. Then, last night, Sofia partied with Paris Hilton at Catch last night and tried to avoid questions about whether she's responsible for the demise of the Spider-Man star's marriage.

Here's the thing -- when we asked her questions about the alleged romance, the teen got feisty ... fast.

Lionel's young daughter, who was outfitted in a sexy leather number, was quick to comment on the "dumb questions" and said, "Are you f--king kidding me?" Nope, we aren't! We wanna know!

Sorry, Sofia, if you didn't want to be seen, you wouldn't go to Catch (the hottest spot in town) with Paris Hilton! Umm ... duh!

Of course everyone is talking about the fact that the 18-year-old got caught on camera getting cozy with the father-of-two just weeks before his separation with Jennifer, which was announced earlier this week.

Hmm ... we have a feeling that Bieber's castaway is secretly loving all this attention!