Once, ages ago, when I was instructing at the Fiesta Americana, I left my weight belt out at the end of the pier. Went to fetch it after 5pm and watched a "log" floating under the surface right in front of the pier.. It was a nice big croc heading south! Luckily no one was in the water. I assume he was going home to Chankanaaab.
Another time, a friend of mine offered to walk her boss's beautiful black lab up north of the Melia. He ran and jumped into the pond behind that ruined house up there and, in front of her eyes, a croc attacked and did the "killing roll". Really sad. (She didn't get fired).
About the same time, two labs off of someone's yachts in Puerto Abrigo were lost the same way.
If anyone remembers all the sweet dogs that used to hang out at La Caleta years ago, several of them met the same fate during the night. Bennie who used to live at that marina reported seeing the crocs leap out of the water to grab the dogs that were sleeping too close to the edge.
And even though I also know of no reports of any tourists being bothered, last July a local guy who was spear fishing from shore a little south of Playa Corona was attacked by a croc. He survived but was hospitalized with wounds to his arms and hands.......(and ummm, got in trouble for fishing in the park too......karma).