KANSAS CITY, KAN. ? The federal fraud trial of former Westar Energy Inc. chief executive David Wittig and his top deputy ended Monday in a mistrial after jurors could not reach a verdict on more than half of the charges.

U.S. District Judge Julie Robinson decided not to hear the jury’s verdict on the remaining charges, all of which related to money laundering. The jury deliberated for more than six days after a trial that lasted more than seven weeks.

The jury deadlocked on a single charge of conspiracy, and several counts of wire fraud and circumventing internal accounting controls. Robinson had directed the jury to resume deliberations on Friday after they initially reported they could not reach a verdict on those counts.

Wittig, of Topeka, and former Westar executive vice president Douglas T. Lake, of New Canaan, Conn., each faced a total of 40 counts related to allegations they tried to loot the largest electric utility in Kansas. The pair left Westar late in 2002; Wittig resigned, and Westar’s directors placed Lake on an indefinite and unpaid leave.

Because the court did not record a verdict, prosecutors can retry the case.

Both Wittig’s attorney, Adam Hoffinger, and Edward Little, the lead attorney for Lake’s defense team, declined to comment. Messages left with Jim Cross, a spokesman for the U.S. Attorney’s office in Kansas, were not immediately returned.

If convicted, prosecutors intended to force Wittig and Lake to give up all assets and salary received during their time at Westar. Prosecutors estimated totals of $27.9 million for Wittig and $9.4 million for Lake.

The two men were accused of using company planes for personal travel; pushing the company to invest in or buy companies in which they had personal interests; manipulating a proposed merger of the utility to bring themselves millions of dollars; abusing an executive relocation program; and conferring with Westar’s outside legal counsel to remove members of the board critical of their compensation.