Marvin Riley once worked for the man who came after RCMP. (CBC)

An 87-year-old East Preston man was stunned with a conductive energy weapon twice on Wednesday after he lunged at officers with a knife, say RCMP.

Staff Sgt. Scott Warnica told CBC News that just before 6:40 p.m., officers got a call about someone who was tearing ribbons off the cars at the East Preston Business Centre parking lot on Highway 7.

When the lone officer arrived at the scene, he was directed to the suspect's home.

Warnica said when the officer went to the home, he was confronted by an elderly man who threatened him and then chased the officer onto the yard.

The officer drew his gun but the man continued to lunge toward him with the knife, Warnica said.

Plain clothes officers with the Halifax Regional Police came to help.

"The suspect would not back away from the officer with his gun drawn," Warnica told CBC News.

"The suspect still wouldn't back away when the two additional police officers showed up and he did not back down when the Taser was initially deployed."

Officers used a stun gun on the 87-year-old man, but only one dart struck the man during the first shot, said Warnica. When the man was hit with the second jolt, he dropped the knife and was arrested.

Marvin Riley told CBC News he's known the elderly man for decades and even worked for him.

Riley said lately the man has become confused and agitated and even attacked another man with a large stick because he thought the man was on his property.

Riley said he thinks police did what they had to do.

"I think if they hadn't used the Taser they wouldn't have taken him now that's my opinion of it. He was a little man, but he worked all his life and he was in shape," Riley said.

The suspect was taken to hospital for treatment.

RCMP said the elderly man will be charged with assault with a weapon and will be released on conditions with a March court date.

Riley said he hopes the man isn't treated like a common criminal.

"It is his mind because I've known him and if his mind was right, he wouldn't have been that way."