Investigators are looking into the possibility that a charter jet that crashed in Colombia while carrying 77 people, including a Brazilian football team, may have run out of fuel, authorities said on Wednesday, according to dpa. The Lamia Air Regional Jet 885 crashed Monday evening in a mountainous area less than 40 kilometers from its destination, Medellin's Jose Maria Cordova de Rionegro Airport. Seventy-one people were killed, including players of the Chapecoense AF football club. Colombian civil aviation director Alberto Bocanegra told RCN Radio that an empty fuel tank was one hypothesis being examined by investigators. Among the data they are reviewing are the plane's flight recorders and a voice recording of the pilot's radio contact with Rionegro, in which he appeared to report fuel trouble but did not declare an emergency. Bocanegra said if the plane had indeed run out of fuel it would indicate an "act of negligence" by the pilot, who was responsible for ensuring fuel supplies were adequate for the trip. Colombian media were the first to point out that the plane appeared not to have exploded or burned upon impact, suggesting a possible absence of fuel. Authorities had earlier said the pilot reported electrical problems shortly before disappearing from radar around 0300 GMT Tuesday. Experts said electrical problems could also have been caused by a fuel shortage. Lamia director Gustavo Vargas told Bolivian television that the plane may have skipped a planned refuelling stop in northern Bolivia because the airport was closed. The 71 dead included seven crew members, 21 journalists and 19 Chapecoense players. Brazilian Air Force planes flew about 200 members of victims' families to Rionegro on Tuesday night to identify bodies so they can be repatriated. Chapecoense defenders Alan Ruschel and Neto and reserve goalkeeper Jakson Follmann as well as a Brazilian journalist and two Bolivian crew members survived with serious injuries and remain hospitalized in Colombia. Follman had his right leg amputated Tuesday. The team's third goalkeeper, Nivaldo, told Brazilian media Wednesday he would retire from football in the wake of the tragedy.