In the first version, the incident began on October 18 by a Greek soldier running after his dog, which had strayed across the border from Greece at the pass Demir Kapia [bg] on Belasitsa (Belles).

[10] The Greek government, led by General Theodoros Pangalos, issued an ultimatum to Bulgaria of 48 hours[11] to punish those responsible,[12] an official apology,[13] and two million French francs as compensation for the families of the victims.

[15] Fighting between Greek and Bulgarian forces started, and Bulgaria appealed to the League of Nations to intervene in the dispute.

Some chetas of the Internal Macedonian Revolutionary Organization (IMRO), together with the sentries, organised defence lines against the Greeks near Petrich.

[17][18] In fact the League of Nations sent a telegraph to both countries to order them to stop their armies, just a few hours before the Greeks launched their attack.

[20] The League Council sent military attaches from France, Italy and the United Kingdom to report to it when the hostilities ceased and to observe the withdrawal of the Greek troops.