The public questioned Tuesday why Boise police fatally shot a mountain lion, but Idaho Fish and Game officials say the cougar became too much of a risk when it moved from East Boise’s outskirts to near Downtown and the Boise State campus.

The 2-year-old female was sighted numerous times near the Greenbelt, Julia Davis Park and BSU on Monday, and Fish and Game officials told Boise police to kill the big cat if they could do it safely. They did, after Boise State employees saw the cougar in a trash bin near the student union.

“Boise PD was acting on our behalf,” said Matt O’Connell, a senior conservation officer with Idaho Fish and Game. “The cat just seemed to be wandering deeper and deeper into town.”

Downtown has too many people, he said. “We’ve had a lot of concern from people wanting to know if the Greenbelt was safe.”

O’Connell said he had mixed emotions, especially since the mountain lion was young and likely had been kicked out by her mother and was trying to find her own territory.

“I feel bad for the animal,” he said. “I always hope they just disappear” and go back to the wild.

The cougar was spotted Friday eating a deer in Warm Springs Mesa and again Saturday, and officials had hoped to scare her back into the East Boise Foothills so she could continue her behavior in her natural territory.

“Unfortunately, the cat stayed in town,” O’Connell said. “The cat had crossed the line between normal cat behavior to hanging around in town and kind of becoming habituated to human activities.”

It’s at least the fifth cougar killed in Boise since 2004. On Tuesday in Santa Monica, Calif., police shot and killed a juvenile male mountain lion that had made its way into the courtyard of a downtown office building.

Online commenters questioned the decision to kill the lion in Boise instead of tranquilizing it and returning it to the wild. In an unscientific poll on the IdahoStatesman’s Facebook page, 169 people said the cougar should have been relocated; 52 agreed with killing it to protect public safety; and 16 people said it was behaving as cougars do and should have been left alone.

Fish and Game officials haven’t had much success tranquilizing mountain lions that become accustomed to people, O’Connell said.

And relocating a cougar can put other communities at risk once the animal sees urban areas as sources of food. Cities offer a wealth of small animals, such as squirrels, rabbits, pigeons, stray cats and even other pets, that are hard for cougars to resist, he said.

Also, relocated lions can easily be killed by an established adult already living in the area, he said.

Tranquilizers are controlled substances that require training to use, and they could cause serious injuries if a dart is lost in a park or other area where a child might find it, O’Connell said.

Cougar attacks on people are rare. O’Connell said cases have been documented in communities in Colorado and California, but there have been no humans killed by mountain lions in Idaho since 1890.

The cougar was first sighted at Warm Springs Mesa feasting on a deer carcass. It was in a yard in the 2500 block of S. Mill Point Way, just north of where Warm Springs Avenue splits and becomes East Barber Drive. That area is right on the edge of the Foothills, which is natural territory for a mountain lion.

It was spotted just before 5 a.m. Monday near the Whole Foods construction site between Myrtle and Front streets, north of Julia Davis Park, then on the Greenbelt near Bronco Stadium. It was around then that Fish and Game officials recommended to Boise police that they shoot the cougar for reasons of public safety, police spokesman Charles McClure said.

BSU employees reported seeing the cougar near a student union trash bin about 11:30 Monday night. Police arrived and fanned out, and an officer who was armed with a rifle saw her walk across the Greenbelt just north of the stadium. That officer shot the cougar in the body from about 40 feet away, O’Connell said, then fired a second shot at close range to ensure that the cat was dead.

The cougar was estimated to weigh between 50 and 60 pounds. It could have doubled that weight had it grown to full adulthood.

A necropsy will be performed, but the cat appeared to be a healthy juvenile just looking for food, O’Connell said.

It’s not uncommon for a mountain lion to follow a river or irrigation canal into town, but it’s unusual for the animal to decide to stick around.

Wildlife officials killed a 60- to 70-pound juvenile last September in the parking lot of Boise’s Saint Alphonsus Regional Medical Center, after it was seen near BSU and the Boise River for several weeks.

Fish and Game officials shot and killed mountain lions in the Warm Springs Avenue area in 2004 and 2006, and a police officer killed a mountain lion in an East Boise backyard in 2008.

Patrick Orr: 377-6219