A Homeland Security Department spokesman was held Wednesday on felony charges of sexually preying on a detective posing as a 14-year-old girl through explicit online conversations. He was quickly suspended without pay from one of the nation's top crime-fighting agencies.

The arrest of Brian J. Doyle, 55, raised doubts about the ability of an agency responsible for safeguarding the country to ensure the security credentials of its own people.

Doyle is accused of 23 felony charges related to sexually graphic conversations with what he thought was a teenage girl, who was in fact an undercover Florida detective. The charges, lodged Tuesday night by the Polk County, Fla., Sheriff's Department, included 16 counts of sending pornographic movie clips to a minor.

Doyle, who lives in suburban Silver Spring, Md., was being held at a nearby detention center as Florida seeks to extradite him.

Homeland Security press secretary Russ Knocke said the department is "cooperating fully" with the criminal investigation in Florida, adding that Doyle's security clearance, employee badge and facility access permissions have been suspended.

"We take these allegations very seriously," Knocke said.

The department's inspector general also is investigating the allegations, which say Doyle revealed his name and his employer and offered the numbers of his Homeland Security-issued office and cell phones during the sexual online conversations. Officials were also examining Doyle's office computer for any evidence.

Authorities said Doyle also sent non-sexual photos of himself. They included one of him in Homeland Security headquarters, wearing an agency pin on his lapel and a lanyard that says "TSA," which stands for the Transportation Security Administration, a branch of the department for which he once worked.

Homeland Security also oversees an Operation Predator unit, which investigates child predators and pornographers.

Doyle appeared Wednesday afternoon at a court hearing in Rockville, Md. No bail was set, and he only spoke to answer routine questions, such as verifying his name. He was joined at the hearing by a woman that his attorney, Barry Helfand, identified as Doyle's life partner of 15 years.

Helfand said he hopes Doyle will be allowed to post bond so he can turn himself in to authorities in Florida without the need for extradition. His next court appearance in Maryland is scheduled for May 4.

The defense attorney said Doyle had lost a brother and a sister in separate incidents — one in a car accident, one during surgery — several years ago around March or April and that could have triggered depression at this time of year.

Doyle was arrested at his home Tuesday as he was online with the supposed girl. An undercover detective had called Doyle at work and said she got a Web camera as he had asked and wanted to test it, said Carrie Rodgers, Polk County Sheriff's Office spokeswoman.

"He said he would get on the computer when he got home from work so we knew he would be on," Rodgers said. "When (police) went to his door, he was on the computer in the middle of a conversation with the girl."

The charges accuse Doyle of finding the teenager's profile online and allege that he began having sexually explicit conversations with her on the Internet on March 14.

On several occasions, Doyle instructed her to perform a sexual act while thinking of him and described explicit activities he wanted to have with her, investigators said.

The arrest "raises serious concerns about the department's hiring policies and, more important, its security clearance practices," said House Homeland Security Committee Chairman Peter King, R-N.Y.

Pledging to investigate those practices, King said Doyle may have used a government-issued computer to "provide potentially sensitive information over the Internet to a complete stranger."

"What if the person on the other end had been a member of al-Qaida or a similar terrorist organization and used this information to blackmail Mr. Doyle?" King said.

It was not immediately clear when Doyle received his security clearance, which gave him access to sensitive Homeland Security information. A senior Homeland Security official, speaking on condition of anonymity because it involves a personnel issue, said Doyle's security screening consisted of an FBI background check but did not include a psychological exam.

The clearance was valid for five years; Doyle was hired by the federal government, at the Transportation Security Administration, in 2002, officials said. He previously worked, for 26 years, as a reporter at Time magazine in Washington. A former colleague said Doyle is divorced.

Neighbors in Doyle's leafy neighborhood said they were surprised that the mild-mannered security employee was nabbed in the undercover sting. Doyle's house is just behind an elementary school yard.

"I was shocked because I didn't think it was something he would do," said neighbor Asha Andreas. "He was gone a lot working. It worries me, too, because I have three kids."

Law enforcement agencies in Florida and other states have focused on conducting stings in recent years to catch people trying to lure children for sex over the Internet. The agencies set up fake profiles of young boys and girls and then wait for predators to take the bait.

Doyle's arrest capped a number of other security breaches at Homeland Security, still in its fledgling stages after being created in 2003 in response to the Sept. 11, 2001, terror attacks. Other security problems include inadequately trained guards at the department's headquarters in Washington and vulnerable information-sharing systems that could allow classified intelligence to be accessed without authorization.