German newspaper Handelsblatt has reported that Audi developed software in 1999 that parent company Volkswagen eventually used to cheat emissions tests. In September, VW admitted to implementing defeat devices to cut diesel engine emissions in 11 million cars from its Audi, Porsche, Seat, Skoda and Volkswagen brands.

Citing industry and company sources, the newspaper indicated that Audi engineers developed the software to support turning off engine function but it wasn’t actually deployed until 2005, when VW engineers were struggling to meet legal thresholds for nitrogen oxide omissions.

Both VW and Audi declined to comment on the news release, deferring to a report into the scandal to be published at the end of April by U.S. law firm Jones Day.

On April 22, VW is set to discuss the costs of the emissions scandal and approve reported earning for 2015. This follows a deadline set for the previous day for VW to reach an agreement with U.S. regulators on a solution for U.S. cars that make use of the software.