Ouagadougou - A second set of tests on the suspected remains of Burkina Faso's iconic ex-president Thomas Sankara have returned inconclusive, with "no DNA profile" to confirm it was his body, the family's lawyer has said.Sometimes referred to as Africa's "Che Guevara", Sankara died during a coup d'etat in October 1987 with the circumstances of his death a mystery. Although the 37-year-old former army captain's death certificate said he died of "natural causes", several reports have suggested he was executed by a hit squad at government headquarters. In May 2015, remains believed to be those of Sankara and 12 colleagues were exhumed from a cemetery in the capital Ouagadougou as part of an investigation into their deaths.An autopsy conducted in October of that year showed his body had been "riddled with bullets" but further tests were needed to confirm a DNA match, the family said. However, genetic tests carried out in southern France were inconclusive, with a police laboratory saying in December 2015 that due to the state of the remains it was impossible to detect any DNA. The family contested the results and in July 2016 a judge ordered that a second round of testing be carried out in Spain.But on Monday, the family's lawyer Benewende Sankara - who is no relation to the former president - said the Spanish tests had returned the same result. 'No match found' "Following this new analysis, no genetic profile match was found for these markers... which means the result was exactly the same as the first analysis, namely a negative result because it was not possible to identify the DNA," he said. "This means that the request of president Thomas Sankara's family that the DNA be identified has not succeeded."Family members would wait to see what the judge said before deciding what to do next, he said. "It is unfortunate, even sad to realise that this has not been possible but it does not end the (investigation) procedure which will go on despite major difficulties in regards to the ability to confirm the DNA" is that of Sankara, he added. A revolutionary figure who is still a hero to many in west Africa, Sankara was killed during a coup that brought his friend and former comrade-in-arms Blaise Compaore to power.A 28-year wait Compaore, who was suspected of ordering Sankara's assassination, went on to rule Burkina Faso with an iron fist for 27 years. During that time, he dismissed calls for an investigation into Sankara's death.His family had to wait until Compaore's ouster in a popular uprising in October 2014 for their requests for an investigation to get the official nod.In total, 13 people have been charged in connection with Sankara's killing, with Ouagadougou issuing an international arrest warrant for Compaore who is wanted for complicity in an attack, murder and conspiracy to conceal a body. The former Burkinabe strongman is currently living in exile in Ivory Coast.Another international arrest warrant was also issued for Hyacinthe Kafando, one of Compaore's former bodyguards who is believed to have headed the unit which killed Sankara.