New details have emerged about the two men accused of participating in the illegal street race that investigators believe caused the devastating crash on Chelopeshko Shose in Sofia, an accident that has so far claimed four lives and left 17 people injured.

Further reading: Another Victim Dies Following High-Speed Street Race Slams Into Sofia Bus, More Victims Fight for Their Lives

According to information gathered during the investigation, the drivers were identified as 28-year-old Vasko Filipov and 34-year-old Trayan Filipov. Despite sharing the same surname, preliminary findings indicate that the two men are not related.

Prosecutors have described both suspects as individuals with criminal records and a history of unlawful activity. The Sofia City Prosecutor’s Office maintains that the men were engaged in a high-speed race through the capital immediately before the collision. Investigators estimate that the vehicles were traveling at approximately 150 km/h.

The crash occurred when the vehicle allegedly driven by Vasko Filipov struck a public transport bus. Authorities say the bus driver attempted to avoid the impact but had no realistic opportunity to prevent the collision because of the speed at which the cars were approaching.