Richard K. Sears, 73, of Pueblo, admitted selling investors on the idea that he was developing a new breed of high-altitude cattle — the Rocky Mountain Romangus — that prosecutors say didn’t yet exist. A longtime hunting outfitter, Sears pleaded guilty in May to mail fraud. Prosecutors say he began enlisting backers in 2008 through mailings targeting people with hunting licenses. Prosecutors say Sears never bought all the cattle he had promised investors he would, and ceased buying new stock at all after 2011, while continuing to raise money. Instead, he used the money to pay off tax debts and to pay back earlier investors, according to court documents. In all, prosecutors say Sears raised around $7 million from dozens of investors and misappropriated nearly $5 million. Sears’s attorney, John Richilano, said his client had begun the venture with honest intentions but, after being dealt a number of setbacks, made some poor choices and dug himself into a hole he couldn’t get out from. Prosecutors described it as a complex fraud that took thousands of hours of investigation to unravel. In addition to a sentence of 41 months in federal prison, Sears agreed to pay $4.97 million in restitution.