Ben Mutzabaugh and Bart Jansen, USA TODAY

A United Airlines pilot has been arrested by police in Texas on charges he ran "a string of brothels in apartment complexes throughout Houston," the Houston Chronicle reports.

Bruce Wayne Wallis, 51, of Houston, was charged with aggravated promotion of prostitution and engaging in organized criminal activity, according to a check of Harris County court records. He was jailed after his arrest Wednesday on $15,000 bond, according to those records.

Police say Wallis was operating "about a half-dozen brothel apartments" with between six and 10 women in each, according to the Chronicle's report.

LOCAL REPORT: United pilot accused of pimping prostitutes in Houston brothels (KHOU TV of Houston)

Court records obtained by the Chronicle allege that the women's services were advertised online and that the women had to pay Wallis $400 a week in the arrangement.

Assistant Harris County District Attorney Lester Blizzard described the alleged brothel operation as "massive" in comments to the Chronicle.

"It's the largest operation that I've ever worked on," he added to the newspaper.

The investigation began in July by the state Department of Public Safety, the Houston police department and the Harris County district attorney's office. Authorities searched 17 locations Wednesday and 12 people were arrested on a variety of charges ranging from misdemeanors to felonies.

"The investigation was worked as a coordinated effort between all three agencies in an effort to combat prostitution and massage brothels in the greater Houston area," the agencies said in a joint statement.

United Airlines says it is aware of the charges.

"We hold our employees to the highest standards," United spokesman Charles Hobart said via phone to Today in the Sky.

Wallis has been "removed from flight duties," but currently remains employed at the company, Hobart said.

Hobart added that United "is assisting authorities in this investigation."