The House Ethics Committee said Friday it is forming an investigative panel to determine whether Republican Rep. Ed Whitfield violated congressional rules by allowing his wife to lobby staff members on issues related to her work.

The committee will examine allegations Whitfield improperly used his official position to benefit himself, his wife or her employer, the Humane Society of the United States.

Whitfield, in his 11th term representing western Kentucky, has called the allegations politically motivated by opponents of his work to regulate the Tennessee Walking Horse industry.

Whitfield's wife, Constance Harriman Whitfield, is a lobbyist for the Humane Society Legislative Fund. She worked with her husband on a bill he co-sponsored to ban a practice that manipulates a walking horse's hooves to produce an exaggerated, high-stepping gait. The practice, known as "soring," is considered abusive by some animal welfare groups.

Whitfield's bill was not approved in the last Congress.

Rep. Kenny Marchant, R-Texas, will chair the four-member investigative panel. Rep. Ted Deutch, D-Fla., will serve as the top Democrat. No timetable was given for their report.

The independent Office of Congressional Ethics said in a report last year that Whitfield likely violated House rules by allowing his wife to use his congressional office as part of her lobbying activities on the bill and other issues related to animal welfare.

Constance Whitfield repeatedly contacted her husband's staff on behalf of the bill and used his congressional office as a base of operations to support the bill, the report said. Both actions are against House rules.

Wayne Pacelle, president of The Humane Society of the United States, said Whitfield's work on the horse protection bill "was entirely motivated by his long-standing and deeply felt passion for stopping animal cruelty."

The groups who brought the Ethics Committee complaint are "engaged in tormenting horses for profit, and this complaint against the author of the legislation is just one of the many obstacles they've tried to place in its way," Pacelle said.