Generally the resistance groups had become increasingly active over the years as their members grew in numbers, gained experience and developed networks.

[3] The city was, however, an important seaport and rail hub for the German war effort with troops and supplies arriving frequently from Germany to be shipped out through the Port of Aarhus to Oslo and Riga.

[6] Combined these factors had made Aarhus an area of particular interest for the resistance movement and it was considered a priority to re-establish new groups that could disrupt German operations.

The first shipment of weapons was collected in July and the first operation against the railway occurred later that month when the rail line to Randers was bombed as a means of testing equipment.

[8] In the fall of 1944, it was considered a possibility that fighting might reach Denmark and a new wing was established within 5 Kolonne, the Demolition Groups (Danish: Nedrivningsgrupper).

The intent of these groups was to destroy vital infrastructure in the event of an allied invasion so as to isolate and immobilize the German garrison in Aarhus.

5 Kolonne was organized around a system of small independent groups, composed of typically 3 members, that primarily interacted with a central commander but rarely with each other.