The massive manhunt for wanted fugitive Brian Laundrie continues as investigators pursue multiple leads.

Survival experts have warned that Brian is either dead or receiving help after more than a month in hiding.

Authorities are leading the search, but everyday citizens are also keeping an eye out in the wake of Gabby Petito's murder.

One Florida resident believes that he may have spotted Brian -- and caught him on camera -- riding a bike along a dirt path.

Much of the search for Brian Laundrie in recent weeks has focused upon the Carlton Reserve.

Brian was familiar with the area and it was not far from his parents' home. It's a logical place to look.

However, authorities have not limited themselves to that region, exploring other leads -- even in other states.

Still, Florida is a good bet for Brian's location, given how far he would have had to travel without his car.

And that's the state where a recent possible eyewitness may have seen him.

The witness spoke to TMZ recently ... and even supplied a video, which you can view on their site.

In TMZ's video, provided by the witness, it appears that an unidentified man is pedaling along a rural road, one likely not found on any maps.

The area is very much outside of public view, which would be deliberate.

The man, who does match the general description of Brian, is riding an old bicycle that has clearly seen better days.

The witness who supplied the video explained that this was recorded by a surveillance camera on the outskirts of his property.

The recording was made on October 9 in Dunnellon, Florida.

The small town is located just three hours north of North Port, which is Brian's hometown and the location of his parents.

The witness explained that there are several acres of rural land behind him.

Whoever the unidentified man in the photo might be, he is taking a rugged sugar sand path that is almost never used.

The man's backpack is visibly oversized and he appears to be struggling while wearing heavy clothing.

A lot of that could match the description of Brian.

A large backpack could be filled with vital survival gear.

Wearing clothing is an efficient way to hold onto it, even in the Florida heat, and anyone surviving in the wilderness will need clothing in the coming months.

Beggars cannot be choosers, so the bicycle could be found, scavenged, stolen, or simply damaged.

Additionally, if someone were hiding from civilization and unable to buy food, that person could be in severe physical distress.

Even a healthy and athletic young outdoorsman might struggle to simply ride a bike if his body is starved of nutrients.

However, all of these factors could point to someone who is experiencing homelessness or extreme poverty.

Not everyone with low quality equipment and an oversized backpack is a fugitive hiding in the woods.

So ... we don't know if this was Brian, and neither does the witness who filmed it.

However, the witness absolutely did the right thing by submitting the surveillance video to the FBI.

Could this be a red herring? Absolutely. It could also be a video of the most wanted man in America.

Turning over the evidence to the FBI (and presumably waiting a while to share the footage with the world) was the right call.