Bulgarian officials say that "human error" on a "dangerous stretch" of highway is the most likely cause of the fiery bus crash this week in western Bulgaria that killed at least 44 people, all of them from North Macedonia and many of them children.
The announcement came on November 25 as the authorities revised downward the confirmed death toll, to 44.
They said they were still searching for another passenger who may have transferred during a gas-station stop before the accident to one of three other buses in the convoy.
A deputy chief prosecutor and chief of Bulgaria's national investigation service, Borislav Sarafov, announced in Sofia that investigators had ruled out a terrorist act and established that there was no explosion.
He said that as the investigation continued, "the leading version [of events] is human error."
Sarafov said the guard rail on that stretch of the Struma highway "is dangerous and is among the main causes for the crash."
A lead investigator, Marian Marinov, said evidence suggested the bus driver had tried to brake before striking the guard rail and noted that it was raining at the time.
SEE ALSO: At Least 46 Dead, Including 12 Children, In Fiery Bus Crash In BulgariaThe bus was one of four traveling together from Istanbul to Skopje in North Macedonia.
At least 12 of the victims were children, and most were tourists from North Macedonia.
Photos shortly after the 2 a.m. crash near the village of Bosnek, near Sofia, showed the bus engulfed in flames with thick plumes of smoke blanketing the highway in both directions.
"Witnesses have said that immediately after the first hit fire broke out and the bus was quickly filled with smoke," Marinov said.
The Macedonian government declared three days of mourning, including the cancellation of all public events, while Bulgaria's government declared one day of mourning.