Republican operatives are intensifying their quest to make the Jens Soering case an issue in the 2012 Virginia Senate race, as they continue despite being rebuffed in their initial requests for documents shedding light on then-Gov. Timothy M. Kaine’s (D) decision to send the convicted murderer to Germany.

Kaine is now the likely Democratic nominee for the seat of retiring Sen. James Webb (D). Former Sen. George Allen (R) is considered the favorite on the GOP side but he faces some opposition in the primary, so in the meantime the National Republican Senatorial Committee is playing the lead role in attacking Kaine.

Soering – who was convicted by a Bedford County Court for the 1985 murder of his girlfriend’s parents – has been the subject of controversy for Kaine since the waning days of his governorship in January 2010, when he decided to permit the transfer of Soering from a Virginia prison to his native Germany. Kaine’s decision was quickly reversed by new Gov. Robert McDonnell (R), and Soering, the son of a German diplomat, remains in the U.S.

Kaine has addressed his rationale for the decision as recently as last month, when he held a press conference in Richmond after entering the Senate race.

“I basically decided, look, Virginia taxpayers had borne the cost of this German citizen’s incarceration for 20-plus years,” Kaine said. “I thought it was time for German citizens to bear the cost of his incarceration.”

But Republicans have tried, so far without success, to find evidence that some other considerations were behind Kaine’s action. Last month, the NRSC filed Freedom of Information Act requests with several Virginia offices and agencies seeking a wide range of correspondence between the Kaine administration, the U.S. Justice Department and other parties regarding the Soering case.

So far, a handful of Virginia entities – including the Brunswick Correctional Center and the Deerfield Correctional Center – have written back to the NRSC, and denied the committees’ document requests.

Virginia’s FOIA law, a Deerfield prison official wrote, “excludes ‘all records of persons imprisoned in penal institutions in the Commonwealth provided such records pertain to the imprisonment.’ Therefore, this record will not be provided to you.”

The NRSC wrote back, contending that the records it is seeking in the Soering case are not covered by that provision of FOIA law and reiterating its document request.

The NRSC also heard back from McDonnell’s office, which pointed the committee toward the archived papers of the Kaine administration at the Library of Virginia.

Kaine campaign spokeswoman Brandi Hoffine said the candidate had been and would continue to be open about the issue.

“Gov. Kaine has publicly addressed this case - both at the time as governor and as a candidate for the United States Senate, Hoffine said. “As he travels the commonwealth meeting with Virginia voters, he welcomes questions on any part of his record. Voters are clearly focused on the need to create jobs and restore fiscal responsibility in Washington and so is Gov. Kaine.”

FOIA requests are a common campaign tool, used to conduct opposition research against any candidate who previously served in government. It will be up to officials in the Republican administration of McDonnell to decide what to release, and there is no reason at this point to believe that the NRSC’s search will yield anything valuable or conclusive.

Still, it’s clear that the GOP doesn’t plan to let go of this issue any time soon.