Three Vancouver teenagers are facing charges after a 16-year-old boy was stripped, beaten and assaulted with a stun device as part of an apparent extortion attempt in Richmond, B.C.

Police responded to a report of an assault underway Wednesday evening in an open field near Alexandra Road and Hazelbridge Way.

When they arrived, they found a teenage boy in the fetal position, stripped of his clothing, badly beaten and surrounded by four males, RCMP said in a news release Friday.

The boy had been kicked several times, some of the blows hard enough to leave shoe impressions on the his body, police said.

One of the suspects also had a "push-stun" device that had left burn marks on the victim's head, RCMP said. A "push-stun" weapon delivers an electric shock when pressed against the body.

Police said some of the males were demanding $200 each from the victim.

He was transported to hospital for a medical assessment and released the same evening.

"This is not a random act, it appears to be motivated by revenge as the victim was described as a bully himself," RCMP Cpl. Jennifer Pound said in the release.

"This act of violence is a retaliation for the bullying the victim has allegedly been doing," Pound said.

All four perpetrators, aged 14 to 17, were released into the custody of their parents.

Pound said RCMP are recommending charges of assault, possession of a prohibited weapon and extortion be laid against three of the youths. The fourth person involved in the assault has agreed to act as a witness, according to police.

Everyone involved, including the victim, are from Vancouver, although the victim works in Richmond.