The incident in fact consisted of three separate nearly simultaneously launched attacks on Latvian border posts by Soviet forces at the early dawn of June 15, 1940.

Shortly before the occupation of Latvia by the Red Army on June 17, 1940, Soviet Special Forces units carried out previously planned acts of provocation on Estonian and Latvian territory.

[1] At 2:30 am June 15, 1940, 25 NKVD commandos managed to cross the Ludza river, which demarcated the Soviet-Latvian border unnoticed.

The attackers most likely intended to capture the patrol post without firing shots because hand grenade packets were placed all around guardhouse except at the front door.

Although visibility was near zero due to the thick fog, Cimoška also opened fire since he understood that the Soviet border guards were attacking.

[2] On June 15, the government of Latvia started an investigation of the attacks and army units together with border guard were put on high alert.

A general mobilization and resistance could be expected however due to the presence of the Soviet military bases in Latvia since fall 1939 such a move was practically impossible.

At Masļenki, three border guards (Jānis Macītis, Pēteris Cimoška, Kārlis Beizaks) and two civilians (Hermīne Puriņa née.

[1] In both Masļenki and Smaili, in total, 37 persons were kidnapped by attacking Soviet troops and brought away to USSR as hostages, of whom ten were border guards and the rest were civilians, including women and small children (as young as one and two years old).