BANGKOK — A security camera footage released by an opposition MP shows moments of an attack on a pro-democracy activist, which still left him in serious condition Sunday.

The footage was obtained from four cameras close to where Sirawith “Ja New” Seritiwat was beaten by four masked men on Friday and released by Future Forward MP Rangsiman Rome, who called the assault a work of professionals.

“One thing I have to stress is that this operation looks professional,” Rangsiman wrote on Facebook. “They knew when Ja New would be at that spot.”

The security cameras show four men on two motorcycles stalking Sirawith after he left his home in Khan Na Yao district on Friday. One pair rode ahead of Sirawith while another followed him from behind until they rushed to beat him with what appeared to be batons.

The assault lasted about 20 seconds before the four attackers fled the scene along Ram Intra Road. All of the attackers wore motorcycle helmets to conceal their identities.

Sirawith remains hospitalized with multiple injuries to his face, skull, eyes and lips. His mother said the attack made one of Sirawith’s eyes protrude from the socket, and he may need facial surgery.

The 27-year-old activist is set to move to Ramathibodi Hospital – his third hospital transfer – later today to receive operations on his respiratory system.

No one claimed responsibility for the attack so far, though the critics of the junta note the incident fit a recent pattern of physical assaults that target prominent activists opposed to the military government.

National police chief Chakthip Chaijinda told reporters he has instructed the investigators to swiftly track down and arrest the perpetrators.