NOVI SAD, Serbia: Serbia began a day of mourning on Saturday as authorities announced an investigation after 14 people were killed when a roof collapsed at a train station. The incident happened early on Friday at the main train station in the northern city of Novi Sad. Residents lit candles and laid flowers at a makeshift memorial for the victims near the railway station and in the city’s main square on Friday, as well as in other towns. New gatherings were announced for Saturday. Authorities have launched an investigation over the incident. Interior Minister Ivica Dacic said on Saturday that “determining responsibility started today.” Dadic told TV Prava that the prosecutor’s office would be questioning 20 people on Saturday “starting from the top, people from the ministries, the public company (Serbia) Railways.” He said that police were seizing documents related to the railway station from the ministry of construction, transport and infrastructure. The Higher Public Prosecutors’ Office in Novi Sad confirmed that an investigation was conducted at the railway station. It said in a statement that it had ordered the “minister for construction, transport and infrastructure be questioned.” According to the same statement, the process of identification of all victims was completed on Saturday. The central railway station in Novi Sad underwent three years of renovation that was completed in July. Serbia Railways said in a statement that the collapsed roof had not been part of the renovations. Serbian President Aleksandar Vucic expressed his condolences and support for the victims’ relatives and vowed to take action. “Those responsible, I assure you, will be punished,” the president said on Friday. Three more people injured in the incident remain in a serious condition, the University Clinic Center of Vojvodina said.