MOSCOW, December 26. /TASS/. The driver of a commuter bus that drove into a crowded underground walkway in the west of Moscow on Monday, presumably did not use the brake systems, GAZ Group said in a statement.

GAZ Group is the manufacturer of the commuter bus that was involved in the accident.

"A preliminary analysis of the details of the incident shows that at the beginning of the movement the wheels of the bus were sharply turned to the right and the bus was moving with a significant deviation from the route. At the same time, it can be assumed that with a high degree of probability the driver did not use any of the listed brake systems of the bus, let alone engine braking, otherwise it is guaranteed that the bus would stop," the company said.

Earlier GAZ offered its experts for working as part of the commission to investigate the causes of the accident. The technical expertise is expected to determine the cause of the accident.

The LIAZ-5292.60 bus, which drove down to the underground passage near the Slavyansky Boulevard subway station, was manufactured by the Likino Bus Plant (LIAZ), which is part of the GAZ Group, in 2016. It was handed over to the Moscow authorities for service on the Moscow suburban routes. The bus was put on the register of the State Traffic Safety Inspectorate on January 4, 2017.

The company also noted that buses of this type are equipped with a certified dual braking system Wabco or Knorr-Bremse.

The accident occurred near the Slavyansky Boulevard metro station in the west of Moscow at around 3:50 pm. A commuter bus cruising between the Skolkovo research center and Slavyansky Boulevard station drove into a crowded underground walkway.

Police sources told TASS the investigators are considering two versions of the accident - the driver lost control of the bus or else the latter was out of service.

The driver was detained and the authorities instituted a criminal case citing the services falling short of security requirements and encroachments on the safety regulations for public transport.

All the four persons who died and eleven others who received injuries were pedestrians.