READING, England—An organized gang of burglars, comprised of four members of the Johnson family and a partner of a family member, was convicted of stealing art and antiquities worth up to £82.5 million ($160 million), British courts announced today. After a month-long trial, the men were found guilty of conspiracy to burgle and of handling stolen goods, and are being sentenced up to 11 years each in prison.

The gang raided homes across several counties between April 8, 2005, and October 13, 2006, with their largest single burglary in Wiltshire, where they stole roughly 300 museum-quality artworks (including a painting by a 17th century pupil of Peter Paul Rubens) estimated at £70 million from the home of collector Harry Hyams.

The BBC reports that while the Wiltshire raid ranks as the U.K.'s biggest ever domestic burglary, the Johnsons carried out other similar heists by first staking out targeted properties, stealing the artwork without leaving a significant trace, and finally escaping in stolen cars.

The gang also targeted commercial merchandise, once stealing £140,000 worth of televisions, china, and glassware from three Worcestershire stores.

"Cases of this gravity must attract heavy sentences because of the deliberate criminality, organization and sophistication of their planning and the effect on the occupants," said presiding judge Christopher Critchlow.

Hundreds of items have already been recovered by the police, and some have even been identified and returned to their owners thanks to the Art Loss Register, which maintains the world's largest database of lost and stolen artworks.