A teenage boy is searching for his puppy after a man grabbed it out of his hands, threatened the boy, and took off, Vancouver police said Tuesday.

Diesel, a 13-week-old pit bull puppy, was carried in the arms of a 15-year-old as he walked down East 53rd street, said Const. Jana McGuinness.

The pair was approached by a man, who asked, "Can I hold your puppy?" she said.

"The boy said, 'No, it's a Christmas gift, I don't want to let it go,'" she said.

That's when the man grabbed the puppy and ran. As he left, he said, "Don't follow me, or I'll shank you," said McGuinnes.

'Shank' is a slang term for a pointed weapon. Police believe the man was carrying a knife.

The incident happened about three weeks ago, said McGuinness.

The boy wants the dog returned because it recently had its ears clipped, and must get his stitches removed soon.

Diesel is about 20 pounds, and is mostly black except for patches of white on his feet, chest and nose.

McGuinness asked anyone who has seen Diesel to call the Vancouver police.