LONDON, ONT. -- Sarnia police say a man trying to protect his neighbour’s property was swarmed on Saturday night and the attack almost cost him his hand.

Police say five people were cutting through a backyard and hopping a fence in the Wellington Street and Murphy Road area around midnight when the resident called out to them to suggest they go around.

They then reportedly pulled the victim to the ground and started kicking and punching him.

At some point, one of the attackers pulled out a knife, slashing the man’s wrist and causing nerve, tendon and artery damage.

The victim was transported to a London hospital and had to undergo an eight-hour surgery, but how much use of the hand he will regain is unknown.

Police say an 18-year-old Sarnia resident, and four suspects under the age of 18, have all been charged with aggravated assault.