The information commissioner has given the government details of police officers who illegally gave out personal information.
The commissioner sent a dossier to the Ministry of Justice as part of a consultation on whether data thieves should be sent to prison.
It contained details of police officers who broke Section 55 of the Data Protection Act. One case in January 2007 saw a police officer give out the address of a pensioner who had been involved in a parking dispute with a 26-year-old woman at a local supermarket.
Her husband and his brother used the information to find the pensioner's house and throw a brick through his window - the 79-year-old later died from the shock.
The police constable involved was fined £1,200 for using the Police National Computer to match the pensioner's address to his vehicle registration number.
In another case an officer from Essex illegally accessed Essex Police intelligence systems on 800 occasions between January 2007 and November 2008.
He passed on mobile telephone records, checked the records of his housemate's two sisters and accessed the record of another man's arrest. He was fined £750.
The information commissioner said in the consultation document, "The information commissioner continues to believe that custodial penalties are necessary if the law is to provide an effective deterrent against the illegal trade in personal data."