RIO DE JANEIRO (AP) — The Supreme Court late Friday approved an investigation of dozens of top politicians, including a former president and leaders of congress, for alleged connections to what they call the biggest graft scheme ever uncovered in Brazil. In total, 54 people are to be investigated by the attorney general in the case involving purported kickbacks at the state energy company Petrobras — though that figure is expected to grow as evidence is gathered. The investigations and any possible trials will take years to play out, but the action throws the young second term of President Dilma Rousseff into further disarray as she faces dueling political and economic crises. Before this week, federal investigators in the kickback case had focused efforts on big construction and engineering firms that allegedly paid over $800 million in bribes and other funds during the decade-long scheme.