Two technicians in Hong Kong have been arrested for tampering with the escalator after a malfunctioning escalator injured shoppers in a mall.

To recap, an escalator at the Langham Place shopping center suddenly went hay-wired and reversed at high speed on Sunday, sending passengers falling down and caused major injuries.

While the actual reason for such incident remains unknown, it is reported by BBC that officials had called in the two technicians, who work for Otis Elevator Company, to assist in investigations hours after the incident.

At the moment, the escalator had been shut down and all workers involved in the investigation were ordered not to get involved with it physically until further notice.

Late on Sunday night, officials, however, noticed that the escalator's auxiliary braking system had been reactivated. Newspaper Apple Daily said the reactivation could have jeopardized the escalator's computer data records.

The two men on the spot were arrested by the police immediately. Otis has expressed shock of the arrests and said it would seek details from authorities.

At least 18 people were injured at Langham Place when the escalator suddenly changed direction and started going down at a speed doubled the original.

Videos of the incident that were captured show dozens of people losing their balance and falling over each other. The situation went out of control when several are seen piled up at the foot of the escalator, with one man lying unconscious on the floor.

At the moment, two people are still in the hospital and are in a stable condition. There has been no official statement yet, but city officials said a damaged driving chain within the escalator, and a malfunctioning braking device, could be behind the incident.

However, the mall claimed that the escalator had last been checked on Thursday, with no problems detected.