Vancouver police have recommended a fourth round of charges in the Stanley Cup riot investigation, but say they're still trying to identify the person responsible for hurling a brick at an unsuspecting officer's face.

In video of the assault, Const. Mike Laurin is seen outside of a Sport Chek store on June 15 as the 2.4-kilogram brick crashes onto his forehead.

Insp. Les Yeo of the Integrated Riot Investigation Team said the impact of the brick would be "the same as getting hit in the head with a puck at 75 miles-per-hour."

"The powder you see there is actually the mortar coming off the brick," Yeo said while screening the shocking footage Monday.

Laurin is then seen stumbling his way into the store, where he received medical attention. The officer received 14 stitches to his head, suffered a serious concussion and was forced to take three months off work.

Police are asking anyone with information about the assault to come forward.

"I know there's somebody out there who can tell us who did this. They may have been standing next to the person that threw it, they may know the person that threw it," Yeo said.

Police also announced Tuesday that 70 fresh charges have been recommended against 25 new suspects, including one accused in the gang beating of Good Samaritan Robert MacKay.

MacKay was standing up to rioters trying to smash windows at The Bay department store when a mob of six men pulled him to the ground and kicked, punched and pepper sprayed him.

Images of the suspects were uploaded to the website when it was redesigned on Jan. 31, and Yeo said three of the six have since been "tentatively identified."

The site has received 24,000 visitors and generated 150 new tips since the revamping, according to police.

The latest charges bring the total number recommended to 250 against 125 suspected rioters. Police have said as many as 700 people could face charges, and that the investigation could take up to two years to complete.

Anyone with information on the riot is asked to call 604-717-9999 or Crime Stoppers at 1-800-222-TIPS.