A New Orleans-based investigation into child pornography led to a 70-year-old Santa Fe resident pleading guilty Monday to a felony count of receipt of child pornography.

In exchange for Robert A. Warren's guilty plea, under which federal prosecutors will recommend that the retired lawyer be imprisoned for five to nine years, the U.S. Attorney's Office dropped four other charges of receiving child pornography and two other charges of possession of child pornography.

"What we can never forget in these child pornography cases is that there are real children — little boys and little girls — who were horribly abused in order to manufacture these images of child sexual abuse," U.S. Attorney Kenneth J. Gonzales said in a prepared statement.

FBI detectives say they began investigating Warren, a recognized Holocaust historian and author whom the agency said had been a licensed attorney in the state of New York, after scouring the names of about 2,500 paid subscribers to a child pornography website in 2006.

According to court records, investigators set up an undercover operation in which they e-mailed those customers an offer for a free trial membership to a child pornography website.

"Each individual e-mail contained a unique URL for the recipient to utilize in responding which was specific to the individual's e-mail address and which would identify to the agents operating the site the e-mail address responsible for the response or attempted connection to the site," said an FBI search warrant affidavit filed in the case.

Warren's e-mail address and the IP address associated to his personal computer were found to have attempted to access the bogus child pornography website seven times, leading to a search warrant being filed that allowed investigators to scour Warren's personal computer for evidence.

That search uncovered, according to the U.S. Attorney's Office, "more than 2,600 images and 26 videos of child pornography."

Attempts after business hours Monday to reach Warren's attorneys, Marc Lowry and Peter Schoenburg, were unsuccessful.

While the charge to which Warren pleaded guilty could have landed him in prison for up to 20 years, the plea agreement states both sides have agreed that the "length of that imprisonment be at least five years and no more than nine years." The plea also allows the court to seek whatever restitution it deems necessary, including a fine of up to $250,000. Warren will have to register as a sex offender once released.

A date for his sentencing has not been scheduled.

Reports in The New Mexican archive indicate Warren had a varied law practice in New York City for 23 years before he moved to Santa Fe in 1991, where he obtained a master's degree in liberal education at St. John's College.

A statement released by the U.S. Attorney's Office said the investigation that led to the current charge against Warren was "brought as part of Project Safe Childhood, a nationwide initiative to combat the growing epidemic of child sexual exploitation and abuse."

Contact Geoff Grammer at 986-3076 or ggrammer@sfnewmexican.com.