The deputy press secretary for the U.S. Department of Homeland Security has been arrested in a sex sting operation on charges of trying to seduce someone he believed to be a 14-year-old girl, Polk County Sheriff Grady Judd said on Tuesday.

Brian Doyle, 55, faces 23 charges in Polk County, Florida, related to use of a computer to seduce a child and transmitting harmful material to a minor, Judd said in a statement.

Doyle was taken into custody at his home in Silver Spring, Maryland, outside Washington, on Tuesday evening while he was on the line with undercover detectives, Judd said.

“He was on his computer communicating with the undercover detective who he believed to be a 14-year-old girl at the time we knocked on his door in Maryland, took him into custody and served a search warrant,” Judd said in an interview on CNN.

The statement said Doyle on March 12 contacted a 14-year-old girl whose profile was posted on the Internet and initiated a sexually explicit conversation. The “girl” was actually an undercover Polk County detective.

In subsequent conversations, Doyle gave the undercover detective his office phone number and his government-issued cell phone number. The statement alleged that the official Doyle used the Internet to send pornographic movie clips to the “girl” and had explicit sexual conversations in online chats with “her,” the statement said.

According to the statement, Doyle also had sexually explicit telephone conversations with a detective posing as a child on his office telephone and cell phone.

Many of the conversations with the “victim” were too graphic for public release, the statement said.

“There is no question that Doyle believed that he was having these disgusting, obscene discussions, on-line and on the phone, with a young girl,” Judd said.

“What stands out to me the most in this particular case was the fact that Brian, on his first conversation with our undercover detective, who he believed to be a 14-year-old girl, clearly identified himself as a deputy press secretary for Homeland Security,” Judd told CNN.

“If he would provide that kind of information to include a photograph of himself with his identification tags, who else may he be talking to around the world who he thinks to be a 14-year-old girl?” Judd said.

The sheriff said Doyle already faces 23 felony counts in the state of Florida and could face charges in a federal investigation now underway.

“We take these allegations very seriously and we will cooperate fully with this ongoing investigation,” DHS spokesman Russ Knocke said in a statement.

A Homeland Security official said Doyle was expected to be put on administrative leave on Wednesday.