In the audit domain it is agreed that a comprehensive understanding of business processes is crucial for the effectiveness and efficiency of internal and external audits on financial reporting or regulatory compliance. However, a review of current modeling methods revealed that domain specific concepts are not comprehensively supported and only little empirical research has been performed on what modeling concepts are required to support an understanding of business processes from an audit perspective. For this reason, we conducted 17 semistructured expert interviews to reconstruct key concepts of the audit domain especially focusing on process audits. As a result we present twelve relevant audit concepts and their relations in a concept map. Unlike for concepts, the expert understanding of concept relations was quite diverse. We interpret this result as an indication of complexity for the topic in focus. The presented concept map is a first step towards a domain specific modeling language.