PORTSMOUTH — A 47-year-old Portsmouth man pleaded guilty in federal court in Providence on Wednesday to one count of distribution of child pornography.

Adam C. Cobb was arrested in April 2015 at his home at 91 Lilac Lane, following an investigation by agents from Homeland Security Investigations (HSI) and members of the R.I. State Police Internet Crimes Against Children Task Force (RI ICAC).

According to court documents and information presented to the court, in January 2015 The National Center for Missing and Exploited Children reported to the RI ICAC that a Rhode Island individual uploaded images of child pornography to Tumblr.com. The investigation determined that an internet address at Mr. Cobb’s Portsmouth residence was the address used to upload the images.

On March 5, 2015, ICAC Task Force members and HSI agents, supported by Naval Criminal Investigative Service agents, executed a court-authorized search warrant at Mr. Cobb’s Portsmouth residence and seized various digital media, computers and cellular phones.

Additionally, the next day, a cell phone was seized from Mr. Cobb by customs and border patrol agents at the Dallas/Fort Worth International Airport as Mr. Cobb entered the United States, having traveled from Tokyo, Japan.

A forensic examination of the digital media seized resulted in the discovery of photos and videos of child pornography depicting two juvenile females. With the assistance of the Baltimore, Md. Police Department and HSI offices in Baltimore and in London, England, the RI ICAC determined the identity of both females. Investigators determined that both juvenile females were known to Mr. Cobb.

Mr. Cobb, who was arrested on April 3, 2015, charged by way of a federal criminal complaint, is currently free on $1 million surety bond. He is scheduled to be sentenced on May 19 by U.S. District Court Judge John J. McConnell, Jr.

Mr. Cobb’s guilty plea was announced by U.S. Attorney Peter F. Neronha; Matthew J. Etre, special agent in charge of HSI for New England; and Col. Steven G. O’Donnell, superintendent of the R.I. State Police.

The case is being prosecuted by Assistant U.S. Attorney Terrence P. Donnelly.