During the night of 13 to 14 April 1945, BS fighters from the municipality of Kollumerland seized control of the sluices at Dokkumer Nieuwe Zijlen, with the mission of securing them. There were fears that the German forces might attempt to blow them up — an act that would have had disastrous consequences.
About a kilometre south of the sluices, four BS groups took positions at a crossroads and held out for over 36 hours. As part of this action, a German bus attempting to flee westward was ambushed on the Soensterdijk. A fierce firefight ensued, in which Pieter Postma was fatally wounded.
On Sunday 15 April, a German soldier on a motorcycle approached the Soensterdijk from the direction of Kollumerpomp. When confronted by BS fighters, he raised his hands in surrender. While the men were disarming him, a truck carrying heavily armed German soldiers and their Dutch collaborators suddenly appeared. In the ensuing firefight, Gerrit Bleeker and Jacob de Graaf were killed.
On Monday 16 April 1945, a relief team was on its way to reinforce the BS group at Soensterdijk when two vehicles appeared from the direction of Kollumerpomp. Believing them to be Canadian forces, the BS guards made a fatal mistake — they were Germans. During the confrontation, commander Heine de Bruin was shot and killed.
Nowhere else in Friesland did the resistance fight so often and so fiercely against the German forces and their collaborators as they did between 13 and 16 April. At least 23 Germans were killed during the battles, and around 160 prisoners were captured by the BS.
Gerrit Bleeker (born 20 February 1909, Leeuwarden), notary candidate in Kollum – buried at the General Cemetery in Kollum. A street in Kollum bears his name.
Jacob de Graaf (born 5 November 1902, Kollum), farmer – buried at the General Cemetery in Kollum. A street in Kollumerpomp bears his name.
Heine de Bruin (born 2 March 1920, Oudwoude), cattle farmer – buried at the Dutch Reformed Cemetery in Oudwoude. A street in his village bears his name.
Pieter Postma (born 2 April 1913, Buitenpost), house painter – buried at the Dutch Reformed Cemetery in Kollumerzwaag. A street in his village bears his name.