Authorities are accusing a United Airlines pilot of running brothels in the Houston area.

Prosecutors say Bruce Wayne Wallis ran more than six brothels, each with eight to 10 prostitutes. Authorities allege Wallis got $400 per week from each of the women. Some of the brothels were in office buildings.

Wallis made his initial court appearance Thursday after his arrest following an eight-month investigation by the Texas Department of Public Safety and the Houston Police Department's human trafficking division.

The 51-year-old is charged with engaging in organized criminal activity and aggravated promotion of prostitution. He's free on bonds totaling $15,000.

Court records didn't list an attorney for Wallis, and attempts to reach him weren't immediately successful.

United Airlines says it's working with authorities and has removed Wallis from his flying duties.