The South Korean prosecution once again summoned for questioning the chief of German automaker Volkswagen’s local operations on Friday, continuing its investigation of alleged irregularities committed by the automaker in the country.

Johannes Thammer, the chief executive of Audi Volkswagen Korea, appeared at the Seoul Central District Prosecutors’ Office the day before to address allegations that the firm fabricated emission test results for vehicles sold in Korea.

The German automaker is charged with rigging the test results of its vehicles’ noise levels, fuel efficiency and emissions testing to obtain local government approval to sell its cars in Korea.

After undergoing questioning for about 16 hours on Thursday, the foreign executive was summoned again at about 10:30 a.m. on Friday for further investigation, the prosecution said.

“First of all, I want to say that I am sorry for the situation and we will do everything, faithfully, to cooperate with the prosecutor,” Thamer told reporters in English before entering the prosecutor’s office on Thursday.

Thamer, who has been in charge of the import and sales of Volkswagen, Audi and Bentley cars in Korea since December 2012, did not comment on whether Volkswagen’s German headquarters were involved in the rigging process.

Last week, the Korean Ministry of Environment banned the local marketing and sales of 80 VW, Audi and Bentley models and handed VW’s Korean unit a fine of 17.8 billion won ($16 million).

By Sohn Ji-young (jys@heraldcorp.com)