Thinking he is communicating with child pornographers, Robert Diduca, of Milford, e-mails federal agents in Boston a photograph of an anguished toddler holding a toy bunny. The child, about 18 months old, had been sexually abused.

After nearly a year-long absence from an online forum used by child porn voyeurs, Diduca returns. Agents, deciding they have enough evidence, arrest him. They find 27,000 child porn pictures and videos on laptops, flash drives and cellphones in Diduca's home and office, including more images of the boy. Some show him being raped.

A detective in the Netherlands sees the first photo sent by Diduca, which investigators posted on a secure international database. She recognizes the toy bunny as a popular Dutch children's book character and contacts Boston. The child could be from the Netherlands, she says.

A television program in the Netherlands, similar to America's Most Wanted, airs a sanitized version of the picture of the boy with the bunny. The child's father-in-law sees it and recognizes his grandson. He also raises suspicions about a man who used to baby-sit the boy. The child's mother calls police.

Amsterdam police arrest the baby-sitter, Robert Mikelsons. He eventually confesses to molesting 87 children, including the boy with the bunny.

Boston agents travel to Amsterdam to gather additional evidence from the Mikelsons case. It leads them to more child porn suspects in the US.

Boston agents return to the Netherlands, where they interview Mikelsons for 16 hours over 2 days. He provides them with additional details that result in more US arrests, as well as leads which investigators are still pursuing.

Mikelsons is convicted in an Amsterdam court and receives an 18-year jail sentence.

Diduca, who pleaded guilty to child porn charges, appears in federal court in Worcester. He is sentenced to 18 years.

Several men in the US are arrested in connection with the case. Investigators allege they talked about cannibalizing children. The chain of evidence goes all the way back to Diduca.

Using clues gleaned from Robert Diduca's e-mail chats, federal investigators and local police in Arizona searched the house of Brandon Jones, who admitted to sexually abusing his 5-year-old nephew. Jones was sentenced in March 2012 to 35 years in state prison and is facing additional prison time on federal child pornography-related charges.

Contacts between the Netherlands' Robert Mikelsons and Gary Myers, a US Army soldier stationed in Hawaii and serving in Iraq, led to Myers' arrest for helping to produce online child sex shows from the Philippines. He pleaded guilty to child pornography charges in June 2012 in US military court and received a 5-year prison term.

Following online communications from Mikelsons, law enforcement officials arrested Brian Robinson in Mississippi, who eventually pleaded guilty to child-pornography charges. Robinson admitted to creating child pornography using his young son and distributing it in the US and abroad. In June, Robinson was sentenced to 60 years in federal prison.

Law enforcement officials arrested Eric Schuster in Wisconsin, after he was found to possess images depicting sexual abuse and exploitation of children. Schuster, who had been communicating online with Mikelsons, was sentenced to nearly 22 years in prison in 2011.

Based on information found in Diduca's computer files, law enforcement officials tracked down and arrested Shawn McCormack, who was charged with multiple counts of child sexual exploitation for allegedly molesting a young boy in a hotel room. His case is pending.

Following leads gathered from McCormack's files, law enforcement officials located and arrested Joshua Taylor in Florida, charging him with child-pornography charges. In May 2012, Taylor pleaded guilty to one count of distribution of child pornography and is awaiting sentencing.

Based on content found in Schuster's computer files, law enforcement officials arrested Michael Arnett of Roeland Park, Kansas. He was charged with producing and possessing child pornography. Arnett's collection included pictures of a naked toddler in a roaster pan. His case is pending.

Using clues found in Arnett's computer files, agents arrested Brown, a puppeteer who allegedly discussed "kidnapping, sexually abusing, murdering and eating of children" with Arnett, according to federal court records. Brown was charged with conspiring to kidnap a child and possessing child pornography.