I don't think he did offed himself either. I think he disposed of a bunch of evidence in that nature preserve, like Gabby's phone, watch, maybe a murder weapon, and then he took off elsewhere.
That would also explain why LE is in no hurry to find a dangerous fugitive and search longer hours. Maybe they are just looking for evidence that he took with him in that backpack.
All speculation on my part. Even with just a body to find, you would think there would be some urgency to find him, due to wildlife in the park. (Gators) And I don't see how they would know for sure he was dead.