The chief executive of a website known for the sexually oriented escort advertisements it hosts was arrested on Thursday and charged with conspiracy and pimping a minor after the authorities raided the company’s Dallas headquarters, according to court records.

The website, Backpage.com, has faced accusations in various jurisdictions of engaging in sex trafficking, and hundreds of trafficking cases across the country have been linked to the site. But this is the first time that criminal charges have been brought against the company or its executives, the authorities said.

Charges were filed in California Superior Court against Carl Ferrer, 55, the chief executive, and two men who founded the company in 2004, Michael Lacey, 68, and James Larkin, 67.

“Defendants have known that their website is the United States hub for the illegal sex trade and that many of the people advertised for commercial sex on Backpage are victims of sex trafficking, including children,” according to an affidavit for a warrant filed by Brian Fichtner, a special agent of the California Department of Justice.

Ken Paxton, the Texas attorney general, said Mr. Ferrer had been arrested Thursday on a California warrant after he arrived in Houston on a flight from Amsterdam, The Associated Press reported. The three-year investigation has been a joint effort of the States of Texas and California.

Carol Robles-Román, the president and chief executive of Legal Momentum, a women’s legal defense and education fund based in New York, said she had been lobbying for action against Backpage for two years, saying the ads it hosts were targeting children.

Backpage describes itself as the second-largest online classified advertising service in the country, according to court records.

“They’re like the McDonald’s of trafficking,” she said in an interview on Thursday night. “They made is so easy.”

The National Center for Missing and Exploited Children said there had been a more than 800 percent increase over the last five years in reports of suspected child sex trafficking, much of it online.

Documents filed in the case included interviews with children who said they took out ads on Backpage.com after they were forced into prostitution.

A 15-year-old girl identified as E.S., who said she was a forced into prostitution when she was 13, said Backpage “profits off of women and men,” whether they want to earn money through prostitution or are forced into it.

“I mean really, coming from someone my age, there is too much access, like it’s too easy for people get on it and post an ad,” she said in court papers.

A congressional investigation this year found that the website changed some of its adult classifieds to conceal the fact that the advertisements were for sex acts with minors. Mr. Ferrer was subpoenaed by a Senate subcommittee last fall to answer questions about reported child sex-trafficking ads, but he did not show up.

The company’s internal reports showed that from January 2013 to March 2015, 99 percent of its income was “directly attributable” to its adult advertising, Kamala D. Harris, the California attorney general, said in a news release. She said more than $51 million of its revenue came from California in that period.

Court records said Mr. Lacey and Mr. Larkin each received a $10 million bonus in September 2014. The United States Supreme Court refused a request by Backpage to block a Senate subpoena seeking information on how it screens ads for possible sex trafficking.