Quote from the Aviation Herald with link:
Crash: LAMIA Bolivia RJ85 near Medellin on Nov 28th 2016, electrical problems, no fuel, impact with terrain
On Dec 26th 2016 Colombia's Aerocivil introduced their preliminary report in a press conference (the preliminary report itsself was not released) stating, that the aircraft did not show any technical fault, there was no sabotage or suicide attempt. The evidence revealed the aircraft suffered fuel exhaustion. The crew was aware of their fuel status and considered fuel stops in Leticia (Bolivia) and Bogota (Colombia), however did not decide to perform such stops. The aircraft was operated at a takeoff weight of 42,148 kg, maximum takeoff weight permitted 41,800 kg, this takeoff weight was not a factor into the accident however. According to cockpit voice recordings the first officer and observer repeatedly calculated the fuel and considered a fuel stop in Leticia but did not follow up as they did not know whether the airport was open. The aircraft features a system that activates an alarm if the fuel remaining was no longer sufficient for more than 20 minutes of flight, however, this system did not activate. 10 minutes prior to impact the crew requested priority for landing and selected the first stage of flaps. The aircraft began to turn and descend without ATC clearance causing separation problem with the other aircraft in the hold. 6 minutes prior to impact engine #3 is the first to flame out, 5 minutes prior to impact the crew selected the next stage of flaps and selected the landing gear down, the crew advised ATC ground services were not needed. Engine #2 fails. 3:45 minutes prior to impact all engines had flamed out, the aircraft was without power, the APU also failed due to lack of fuel. 2 minutes prior to impact the crew declared emergency reporting total power failure. The aircraft impacted Cerro Gordo at a speed of 230km/h below 9000 feet when they needed to be above 10,000 feet to safely cross the mountain.
Seems like Lemme have been pretty spot on with his "investigation". Crew selected both flaps and gear down before the last engine flamed out. The last engine flamed out 3:45 min before impact.