It's not a lake, it's a flooded quarry, very popular for technical training as it goes down to around 90m.
Pedreira (quarry) de Salto de Pirapora.
Here's a link to the best article I saw about this incident. It's in Portuguese but Google translator works very well:
dia a dia | Familiares choram as mortes de mergulhadores | Diário de S. Paulo
The quarry has been out of use for about 10 years.
According to the articles and what I picked up talking to other divers is that one of the divers was inexperienced - only 7 dives and he'd just bought a set of new gear that he was anxious to try out.
The other diver was more experienced - some years of diving.
The bodies were found at 80m. One of the cylinders was empty - not yet clear whose.
Both were using dive computers but the profiles have not been published.
I heard last night from a regular diver at the quarry that the third diver in the group lost contact with the other two, surfaced and then raised the alarm when the other two failed to surface after 40mins.
I'm told it was their 2nd dive.
The problem with this sort of incident is that it creates a lot of pressure to prohibit diving in the quarry - an excellent site for technical training but one that needs to be respected by rec divers, especially inexperienced ones.
The father remarked "This place will keep killing people." as if it's the fault of the quarry.
One of the local residents remarked "The correct thing to do would be to get rid of these three quarries, to avoid the tragedies that keep happening."
