Craig Christensen says he still bears the emotional scars of the night two pit bull dogs almost broke through a glass door at his home.

During testimony Friday in 2nd District Court, the North Salt Lake resident said he shot two pit bulls in his yard in July 1986. Christensen said the dogs - trained to attack people - had escaped from their owner's house, mutilated a cat in his yard and then made continued attempts to crash through his sliding-glass door.He said after telling his children to lock themselves in their rooms, his eldest son opened up the glass door and he shot at the dogs with a shotgun as they lunged at him. He said he had almost allowed his children to sleep outside that night.

"I can only imagine what would have happened if I had let my little kids sleep out that night," he said during the final day of a trial testing the constitutionality of a North Salt Lake vicious-dog ordinance.

North Salt Lake City Attorney Kent Christiansen cited Christensen's testimony in closing arguments to show that the City Council believed pit bulls are a threat to the health and safety of the city when it enacted the ordinance.

Judge Rodney S. Page said he will study testimony made in the case and will mail a written ruling to the parties in the case. He isn't expected to make the ruling until after Feb. 1.

The City Council passed the ordinance in November 1986 to require owners of vicious dogs to keep them in a pen or enclosure at least 6 feet high, leash and muzzle them when out of the enclosure and maintain $100,000 liability insurance. The ordinance defines the American pit bull terrier, bull terrier, American staffordshire terrier, staffordshire bull terrier, tosa and shar-pei as vicious dogs.

The ordinance was challenged by North Salt Lake resident Ralph Greenwood, operator of Greenwood Kennels and a pit bull breeder, about six months after its passage. Greenwood died in February 1988, but the case has been pursued by his daughter, Kate Greenwood. She also took over her father's position as president of the American Dog Breeders Association, a pit bull fanciers organization.

Greenwood's attorney, David White, said in closing arguments that the law should be ruled unconstitutional because courtroom testimony showed that it is difficult even for experts to distinguish between seven breeds of dogs defined in the ordinance as "vicious" and other mixed-breed dogs.

"It lacks clarity for mixed breeds. It has singled out pit bulls as a class. How does a person know it applies to them if they own a dog that is one-eighth or one-quarter pit bull," White said. "How does Joe Citizen know how the ordinance applies when he buys a child a puppy out of a store. The Constitution is aimed at an average person with ordinary intelligence."

He also said that an appeal process outlined in the ordinance was vague and that non-breed-specific ordinances on the books in Salt Lake City, Davis County and Ogden better address the problems of dog viciousness that shows up in all breeds of dogs.

Christiansen told Page that the plaintiff, Kate Greenwood, had failed to show that North Salt Lake overstepped its authority by making legislation directed at dogs generally known as "pit bulls."

"You don't have to regulate every animal in the same way to pass constitutional muster," Christiansen said in response to White's argument that the law unfairly singles out pit bulls.