LOWELL -- Slaps, kicks, cane strikes and pepper spray.
None of it could get a pit bull to loosen its grip on a service dog downtown yesterday.
It took a burst from a fire extinguisher for the canine to finally let go.
"It was definitely disturbing," said Steve Syverson, who owns the art-supplies store Van Gogh's Gear. "It seemed like there was nothing we could do."
Middle Street resident Alfred "Fred" Roberts said he was out on one of his daily walks with Vinny, his wife's service dog, when the attack unfolded near the Life Alive restaurant around noon.
"I saw a pit bull across Middle Street with three people," Roberts recalled last night. "For no reason at all, he charged right across the street and latched onto my dog's throat."
As his black English Labrador repeatedly yelped out, Roberts started beating the pit bull with his cane, to no avail. He said he also injured one of his fingers when he tried to pry the dog's mouth open.
"It sounded like a donkey squealing," Debbie Janes from the New England Quilt Museum said of the Labrador's cries. "It was a strange noise."
Other bystanders quickly joined in the melee, kicking the pit bull as they tried to help.
"There was a lot of commotion," said Gary Rogers, owner of Rogers Pool, Patio and Toy Co. "Someone punched and booted the dog to get it to let go of its neck."