After issuing a tearful apology for an “error in judgment,” former Qwest finance chief Robin Szeliga was sentenced Friday to two years’ probation, six months of home detention and a $250,000 fine for insider trading during the company’s multibillion-dollar accounting scandal.

Szeliga, the highest-ranking executive from Qwest to plead guilty in the government’s case, is expected to be a key witness in the trial of former Qwest CEO Joseph Nacchio, who faces 42 counts of insider trading. U.S. Attorney Bill Leone called Szeliga’s help in that case “very substantial.”