The cat was shot several hundred yards from soccer and baseball fields at the edge of a housing development, said Lorna Bernard, a spokeswoman for the California Department of Fish and Game.
"It's unfortunate that we had to kill it," Bernard said. "It's even more unfortunate that the person who owned it didn't come forward and alert us immediately. We might have been able to capture it."
Trackers had to shoot to kill because a tranquilizer would have taken five to 10 minutes to bring down the animal, Bernard said. They were concerned the animal might attack them or bolt onto a nearby highway. The animal was killed near Simi Valley, about 40 miles northwest of Los Angeles.
Authorities received a call just after 6 a.m. from a resident who reported the tiger strolling past his back fence. He said his children took pictures from inside their home.
Ken Tucker told KCBS-TV the tiger walked to a nearby house and "was just staring down" the neighbor's dogs.
The trackers had been looking for the animal for eight days, using infrared equipment at night. They had set traps with goat meat and chicken.
The hunt began after the discovery of paw prints on a ranch near the library that were far too large for native bobcats or mountain lions. The size of the tracks indicated the animal weighed as much as 600 pounds.
Bernard said the owner could have told authorities about the tiger's temperament and eating habits, which might have helped them catch the animal sooner.
As the cat roamed the hills, it became hungrier and disoriented, making it more dangerous to the nearby community of horse ranches and sprawling homes.
Authorities said they were investigating how the cat got loose in the hills.
"Obviously we'll be looking at all the facilities in the area that housed big cats," Bernard said.
Two weeks ago, authorities removed nearly two dozen large cats, including lions and tigers, from property rented by Abby and Emma Hedengran not far from the library, Bernard said. All the animals that inspectors found on the property were accounted for, she said.
A telephone message left Wednesday for the Hedengrans by The Associated Press was not immediately returned.
Tests will be performed on the tiger that may provide clues about its history.