BERLIN — The police in Germany say they have broken up a sophisticated child pornography ring that peddled “unfathomable images” over the internet, arresting 11 people on suspicion of severely abusing at least three boys, filming the acts and selling them for profit.

Close relatives of the boys, ages 5, 10 and 12 — including one set of parents and an uncle — were among those arrested, the police said Saturday. Investigators identified the suspects from videos recovered from professionally encrypted hard drives that they seized and are still working to unlock, the authorities said.

Despite a decade-long government campaign to combat the sexual abuse of children, more than 20,000 cases of child abuse or pornography are reported each year in Germany, official statistics show.

The arrests announced Saturday are the latest in a string of high-profile abuse cases.

This week, Germany’s federal police announced they were investigating a 43-year-old German on suspicion of murdering Madeleine McCann, who disappeared from a resort in Portugal in 2007 when she was just shy of her 4th birthday. German police say the suspect in the case, identified only as Christian B., may also be responsible for the disappearance of a 5-year-old German girl in 2015.

In the new case and others, sophisticated technology has made it easier for abusers to cover up and profit from their crimes, the authorities say. Encrypted files are sold on what is known as the darknet, which is accessible only by certain software and is used by criminals to communicate without being detected.

The main suspect in the new case, a 27-year-old information technology technician from Münster, encrypted more than 500 terabytes of child pornography, Joachim Poll, who headed the investigation for the Münster police, told reporters on Saturday.

“All of the hard drives are highly professionally encrypted,” he said. “They are so well done that we have not yet been able to access all of them.”

The suspect, who was not further identified, had equipped a specially cooled room in his basement with seven servers holding the images on encrypted hard drives, the police said. Authorities said they believe many of the images were filmed in a cabin fitted with surveillance cameras inside and out, on a countryside property owned by the main suspect’s mother.

That woman was arrested on suspicion of aiding and abetting the abuse, Mr. Poll said. The parents of the 5-year-old and the uncle of the 12-year-old were also among those arrested.

In the cabin, authorities found a video of the 10- and 5-year-old boys being “brutally” raped and sodomized by the main suspect and three other men, Mr. Poll said. He added that he believed the children had been sedated.

“You cannot imagine,” he said.

The children have been placed in the care of social workers and are receiving psychological help, said Martin Botzenhardt, a prosecutor in the western city of Münster. Authorities said they expect to make more arrests as they unlock the encrypted hard drives and uncover more evidence.