FORT WORTH, Texas, Aug. 6 (UPI) -- Gunter Frentz insists his travel business does not operate sex tours, but police in Fort Worth, Texas, say Frentz is "definitely on the radar."

Frentz, 64, operates G.F. Tours, which entices men to travel to Bangkok to enjoy the nightlife in exotic locales.

"I am not calling myself a sex tour operator," he told the Fort Worth Star-Telegram. "We don't provide girls. We do take people to nightlife areas."

Frentz acknowledged that "opportunities do exist to take out a female companion."

He told the Star-Telegram he keeps a low profile to avoid harassment by human rights organizations and women's groups.

Jessica Neuwirth, a founder and president of the New York women's rights organization Equality Now, told the newspaper sex tours exploit impoverished and disadvantaged people.

"This is about human dignity and human rights," she said. "It's the promotion of prostitution, and we think that in some cases, authorities are just giving it a wink and a nod."

Fort Worth police officer Ed Adcock said police have been watching Frentz since last November.

"He's definitely on the radar," said Adcock.