YouTube Rescue Dive Team Claims They've Found Missing Teen Kiely Rodni

A famous search and rescue dive team that inserted itself into the hunt for missing teenager, Kiely Rodni, claims they've found her ... but it doesn't sound like she's alive.

The YouTubers known as Adventures with Purpose -- which has millions of subscribers and followers across their social media channels -- made the claim Sunday, writing on their official Facebook page ... "WE JUST FOUND KIELY RODNI."

They go on to say that she is confirmed to be inside a vehicle that is upside down in about 14 feet of water, adding that the family has been notified and that law enforcement is on their way. As for where exactly they discovered her ... reports suggest it might be in Prosser Lake.

This is where Kiely first went missing weeks ago at the beginning of the month, and the search efforts thus far have been focused on this area. AWP literally just volunteered their service a day or two ago ... vowing to help locate her, and it appears they did just that.

As we reported ... Dog the Bounty Hunter told us he'd been getting tons of tips on her potential whereabouts, but was reluctant to jump into the high-profile missing persons case because of all the blowback he got from the Gabby Petito case.

Kiely went missing on Aug. 6 near Truckee, CA -- where she and a bunch of other youths were partying in the Lake Tahoe region.

She went missing late in the night, apparently without a trace ... and hasn't surfaced since. A massive undertaking has been underway to find her.

No other details have come to light yet as to how Kiely may have ended up in a car and submerged in the lake -- and if foul play is suspected.