The South Florida head of Immigration and Customs Enforcement pleaded not guilty Wednesday to a federal indictment accusing him of child-porn offenses on his home computer, including transporting and receiving images of minors “engaging in sexually explicit conduct,” according to the U.S. Justice Department.

Anthony V. Mangione, 50, of Parkland, was also charged with possessing messages stored on his computer that contained “additional images” of child porn during the same period of the alleged offenses between March and September of last year.

Mangione, arrested Tuesday, showed no emotion at his federal court appearance in West Palm Beach.

If convicted of the three separate charges, Mangione could face up to 20 years in prison, according to authorities. Each of the transportation and receipt charges carries a minimum-mandatory sentence of five years.

Mangione, who worked as a federal agent for almost three decades until his suspension as the regional ICE chief last spring, was taken into custody Tuesday by Broward sheriff’s deputies and FBI agents outside a Publix supermarket in Coral Springs.

Mangione, who is married, is being held before trial at the Palm Beach County Jail pending the outcome of a psychological evaluation requested by the Justice Department. Andrew McCormack, a department trial attorney, said at the court hearing that the government is concerned that Mangione could harm himself.

Mangione’s attorney, David Howard, did not object to the psychological evaluation. Howard told reporters outside the courthouse that given the “nature” and “magnitude” of the charges, prosecutors were concerned that his client might “melt down.”

“There is no such real concern, and he’s going to be released, ” Howard told reporters. A status hearing on Mangione’s detention is scheduled for Oct. 17.

Howard declined to comment about the indictment, saying it would be “inappropriate.”

Federal authorities, who issued a short news release, also declined to comment on the highly controversial case brought against the suspended special agent in charge of ICE’s South Florida office. Mangione had headed the office since 2007.

Mangione’s name often graced news releases lauding the agency’s efforts to fight child pornography, in both the cyber and real worlds. In statements, he talked about using technology to combat child pornography and his agency’s resolve to combat the crime.

“Too many children are victimized by predators that target the most vulnerable among us — our children,” he said in a 2009 news release announcing that a 20-year-old Palm Beach County man was sentenced to more than 12 years in prison on child-porn charges.

In April, Mangione was placed on paid administrative leave after BSO deputies and FBI agents began investigating four images of child porn he allegedly received on his home computer via an AOL email account, according to sources familiar with the probe. The investigation grew significantly over the summer, leading to the alleged discovery of more images of child porn on his computer, sources said.

In April, The Miami Herald reported that the BSO and FBI investigators had seized Mangione’s computer from his Parkland residence after obtaining a search warrant based on an alert from AOL, Mangione’s Internet service provider. The Justice Department probe took months to complete as investigators analyzed his computer and other electronic equipment to determine whether Mangione sent, received, or distributed illegal digital images of children engaged in sexual activity.

AOL, which monitors the distribution of child pornography by its users, alerted a national nonprofit resource center about the images allegedly sent to Mangione’s computer, sources said. The National Center for Missing and Exploited Children then sent the information to a multiagency task force that investigates child-porn distribution over the Internet.

Investigators issued a subpoena to AOL to learn the identity and computer address of the account user who allegedly received the four images, sources said. The information provided the legal basis for BSO to obtain a search warrant allowing investigators to enter Mangione’s home and seize his computer.