Over 200 people, mainly from the country's political and military elite, were killed in the attack and around 500 bystander worshipers, who attended the liturgy, were injured.

[1] After the failure of the September Uprising in 1923 and the prohibition of the BCP by the Bulgarian Supreme Court of Appeal on 2 April 1924, the Communist Party found itself in a difficult situation.

A Special Punitive Group was established as part of the Central Committee of the BCP, including Yako Dorosiev, Captain Ivan Minkov and the future leader of Bulgaria Valko Chervenkov.

The Military Organization (MO) of the BCP, led by Minkov and Major Kosta Yankov, set up small isolated groups ("шесторки", "shestorki", like the current terrorist cells) that carried out individual attacks.

Following the killing of Valcho Ivanov, an influential functionary, on 11 February 1925, an amendment to the Law for the Protection of the State which increased the power of the authorities was introduced on 10 March.

At 20:00 on 14 April, General Konstantin Georgiev, a deputy of the ruling Democratic Alliance, was assassinated by Atanas Todovichin in front of a Sofia church while heading there for the evening service with his granddaughter.

In accordance with the MO group's plan, when the congregation had gathered and the service began, Zadgorski gave Nikola Petrov a signal to detonate, after which the two left the building at around 15:20.

[3] The monarch, Tsar Boris III, was not in the church, as he was attending the funerals of those killed in the attempt on his own life in the Arabakonak pass in Stara Planina.

Zadgorski, Lieutenant-Colonel Georgi Koev, who unsuccessfully attempted to hide Minkov, and Marko Fridman, an MO section leader, were all sentenced to death.

Stanke Dimitrov, Petar Abadzhiev, Dimitar Grancharov, Nikolay Petrini and Hristo Kosovski received capital punishment by default, with the last three of those having already been killed in the previous weeks.