X17 XCLUSIVE - First Heather Sighting Since Her DUI Arrest!

After being arrested Saturday night on suspicion of driving under the influence of a controlled substance in Montecito near Santa Barbara, Locklear -- a free woman -- went out to lunch with boyfriend Jack Wagner yesterday.

And, as you can imagine, she did NOT want to talk about the arrest -- an arrest which now, according to online reports, seems to be coming under suspicion!

TMZ reports that former Us Weekly staffer and photo agency owner Jill Ishkanian was the one who made the 911 call that got Heather busted. Do we smell a set-up?

Ishkanian is currently under investigation by the FBI for hacking into Us Weekly computers after she left the company.

Now, we hear Ishkanian is dating a photographer who works for the photo agency she called to take pictures of Heather's arrest. And TMZ paid a reported $30,000 !!!! - that's what we're hearing, anyway, for the exclusive rights to the photos. Anybody heard of due diligence, y'all? -- ding dang!