A Worcester man who authorities say fantasized about torturing, raping, killing, cooking and eating kidnapped children in his basement dungeon should serve 27 years in federal prison for his crimes, federal prosecutors said in documents filed today.

Geoffrey Portway, 40, pleaded guilty in May to solicitation to commit a crime of violence — kidnapping of a child — and distribution and possession of child pornography.

Portway will be sentenced in federal court next Tuesday.

“Portway has pled guilty to some of the most vile and heinous crimes known to our society, namely participating in the sexual exploitation of young children through the possession and distribution of child pornography and soliciting the kidnapping of a child for the purpose of killing and consuming that child,” U.S. Attorney Carmen M. Ortiz and Assistant United States Attorney Stacy Dawson Belf wrote in their sentencing recommendation.

The documents filed in court today include excerpts from online chats with his alleged conspirators across the country — including the now-convicted Ronald Brown of Largo, Fla., a puppeteer who planned along with Portway to kidnap children he knew through his work with a local church.

Brown even sent Portway a photo of one of the boys “with lines drawn on him to identify the different cuts of meat,” the sentencing memorandum says. They discussed taking that child to a rented house in the Everglades, mutilating him, eating his body over several weeks and feeding the “leftovers” to alligators.

Another boy would have yielded “lots of meat,” Portway told Brown in a chat in which prosecutors say the two lust over the child, photographed by Brown while visiting him at the hospital, where he was recovering from “extensive surgery.”

That chat appears to have given Portway an idea: “just need to open a mortuary,” he writes. “any boy who is scheduled to be cremated, dissapears. (sic) fake ashes given.”

Feds say they began investigating Portway in the summer of 2012 after identifying him as part of an online community obsessed with the cannibalization and rape of kidnapped children. Investigators searched his home and found he had built in his basement a soundproofed, double-locked room containing a “child-sized homemade coffin,” a 3-by-4-foot steel cage, freezers and disposable scalpels.

The investigation was spurred by the probe of a former hotel manager from Milford, Robert Diduca, 48, who pleaded guilty to charges of sexual exploitation of children, and possession and distribution of child pornography immediately following his November 2011 arrest. Diduca was sentenced to 18 years in prison. Prosecutors said he joined an online forum to chat with other predators.

Laurel J. Sweet contributed to this report.