Washington (CNN) -- A high-profile appeal for help from the public to solve three child pornography cases has led to the arrest of two suspects, Immigration and Customs Enforcement announced Friday.
ICE said it took Lance Robert Fries, 43, into custody Friday afternoon at his attorney's office in Tucson. He faces potential federal charges of production of child pornography and is expected to make his initial appearance in federal court Monday, ICE said.
Thursday night, Letha Mae Montemayor, 52, was arrested outside a Los Angeles apartment building after law enforcement officials received multiple tips and located her, authorities said Friday. She is charged with one count of production of child pornography and one count of conspiracy to produce child pornography.
The two arrests came after ICE asked for the public's help in identifying four suspects in three unsolved child pornography cases.
Montemayor, previously known as "Jane Doe," was allegedly involved in one of the cases along with an unidentified man.
Fries, called "John Doe" until he was identified, was allegedly involved in a second case, ICE spokeswoman Gillian Christensen said. The suspect in the third case is still unidentified, she said.
According to ICE, Montemayor was identified as a suspect through the tattoos and her facial appearance and was arrested less than 10 hours after the appeal for tips.
Montemayor is expected to have an initial court appearance Monday. CNN was unable to learn whether she has a lawyer.
"This arrest would not have happened without the public's help, and it demonstrates how much individual citizens can do to help law enforcement attack crime," ICE Director John Morton said in a statement issued Friday.
Her case involves the alleged sexual molestation of an unidentified girl. Investigators believe the abuse took place about 11 years ago when the girl was around 13 years old, but the pornographic images were widely circulated. ICE posted pictures on its website of an unidentified woman and man suspected of abusing the girl.
The woman had very distinctive tattoos visible in the pictures. A criminal complaint alleged the woman is seen in about five images sexually abusing the girl.
So far, law enforcement officials have not learned the name or location of the man suspected in the Jane Doe abuse case, and they are still seeking the public's help in finding him.
The girl whom the pair allegedly abused also has not been identified. ICE officials said they believe she is now an adult.
Morton made the appeal for identifying the suspects at a news conference Thursday in Washington, when he announced the results of Operation Sunflower. It is an international operation aimed at child pornography and sexual abuse in which 245 suspects were arrested and 123 victims of child exploitation were identified.
Late Thursday night, special agents received a call to the ICE tip line regarding John Doe's possible identity.
That case involved the sexual exploitation of a prepubescent boy by an adult male. Investigators were able to identify the victim and confirm that the boy is now safe.
In order to protect the victim's privacy, ICE said it would release no details about his identity or relationship to the suspect.
The pornographic images involving the girl were first discovered by ICE Homeland Security Investigations agents in Chicago in 2007. The pictures were submitted to the National Center for Missing and Exploited Children's Child Victim Identification Program.
ICE determined the images were not related to any known case and the victim hadn't been identified. Through forensic analysis, agents determined the images were taken in the Los Angeles area. A 2001 wall calendar was visible in some pictures, helping officials determine the abuse happened 11 years ago.
In the John Doe case, HSI special agents first discovered the images in Portland, Oregon, in 2006.
The material was submitted to the Child Victim Identification Program, which determined the victim had not yet been identified and was not linked with other known child pornography images.
"This is truly a remarkable turn of events and it again demonstrates the collective power that can be brought to bear when law enforcement and the public team up to combat the sexual exploitation of children," Morton said. "Those who produce and trade child pornography over the Internet believe they're protected by the anonymity of cyberspace. Through our collective efforts, we're proving these predators wrong and gaining justice for their innocent victims."
CNN's Melissa Gray contributed to this report.