Wattana Pummares, 61, a former engineer at Electricity Generating Authority of Thailand (EGAT), was arrested last week as the primary suspect behind the bomb at the hospital.

Security camera footage of the suspect captured on surveillance cameras in several spots on May 22, was key evidence in his eventual arrest.

The photos showed Wattana’s journey from when he left EGAT to travel to the hospital and then leave the hospital.

Police arranged all the photos into the five-minute video and showed it to reporters before a press conference which was held after the military handed Wattana over to police.

Security cameras are often found to be out of order after an incident. However, the cameras provided crucial evidence in this case.

At the end of the video, police credited and thanked the Bangkok Metropolitan Administration, Royal Thai Police, and EGAT for the photos from their cameras.

The Criminal Court last week approved a warrant for Wattana’s arrest for possessing explosive devices and his involvement in four explosions in the city.