A former attorney in Houston who portrayed himself as a real estate investment tycoon has pleaded guilty in a $7.8 million Ponzi scheme. Federal prosecutors in Houston say 67-year-old Billy Frank Davis pleaded guilty Monday to wire fraud. Investigators say more than 20 investigators were scammed. Prosecutors say Davis during the past 10 years pretended to be in the real estate investment business. He used money from investors to pay his previous debts and fund his personal lifestyle. Davis faces up to 20 years in prison when he’s sentenced in early 2013.