Chancellor Gerhard Schroder's Social Democrats have begun probing an alleged party funding scandal. After several recent glitches in the run-up to the September election, scandal is the last thing the party needs.
Scandels and sleaze on both sides of the political divide
Public prosecutors in Cologne are investigating allegations that Norbert Rüther, a senior Social Democrat in the western city, accepted bribes in connection with the construction of a waste disposal plant.
Rüther admitted to "improper behaviour" regarding irregular payments totalling at least 174,000 euro he made to the party between 1994 and 1999.
He is also believed to have issued tax deductible receipts to party members who had never seen the money, let alone actually made the donations.
Ruether avoided scrutiny from auditors by accepting the money in 20,000 mark sums, a threshold under parliamentary rules that meant he did not have to name the donors in his local party accounts.
If found guilty, the SPD will be hit with a large fine and face tough opposition questions in the run-up to September's general election.
Opposition politicians seize on scandal
Opposition conservatives have sought to make political capital out of the case ahead of the elections and are urging the parliamentary commission that assesses party donations to examine the affair.
"It's not just about illegal donations, but bribery too," said Andreas Schmidt, the chairman of the opposition group on the committee.
But the centre-right Christian Democratic Union is itself still recovering from a scandal over undeclared donations that engulfed former Chancellor Helmut Kohl in 1999.
Kohl admitted to having broken party funding rules by accepting 1 million dollars in undeclared, and thus illegal, campaign donations. But he has repeatedly refused to reveal the donors' names.