A recent U.S. Supreme Court ruling requiring proof of kickbacks or bribes in prosecutions involving the theft of so-called honest services left prosecutors with "little choice" but to dismiss charges against two former Westar Energy executives, the U.S. attorney's office said Monday.

"The law no longer supported our position," U.S. Attorney Barry Grissom said in a statement. "We were duty-bound not to go forward with the prosecution."

Former Westar Chief Executive David Wittig and his top strategy officer, Douglas Lake, were charged in 2003 with conspiring to inflate their compensation from the Topeka-based utility and taking steps to hide their actions.

U.S. District Judge Julie Robinson dismissed all charges against them Friday at the request of federal prosecutors.

That prompted Jim Ludwig, Westar Energy's executive vice president, to issue a statement saying the company disagreed with the Justice Department's decision and planned to pursue civil claims in an arbitration proceeding that had been put on hold pending the criminal case. He noted investors, who had borne the damages and expenses, had not received any restitution.