Wells Fargo yesterday settled accusations that it sold troubled mortgage investments without fully researching the products or disclosing the risks to customers, the New York Times DealBook blog reported today. The action by federal authorities, the latest mortgage-crisis case against a big bank, yielded a $6.5 million settlement. The Securities and Exchange Commission has spent nearly four years building cases against the nation's biggest banks for their role in the mortgage mess. The agency has filed civil actions against Goldman Sachs, JPMorgan Chase and Citigroup. But in recent months, the agency has struggled to bring big cases as it pursued a second round of investigations focused on the banks' failure to disclose the dangers of mortgage securities. The Wells Fargo settlement comes just days after Goldman Sachs revealed that the SEC had closed an investigation into a 2006 mortgage deal without pursuing charges.