BILLINGS, Mont. — Wildlife workers on Tuesday halted their efforts to capture a grizzly bear that killed a woman over the weekend near Yellowstone National Park after finding no sign of the animal since the day of the attack.

Amie Adamson, 48, was killed the morning of July 22 while running or hiking alone on a forest trail about 8 miles west of the park, officials said. The bear was traveling with one or more cubs, and officials believe it struck Adamson during a surprise encounter before fleeing the area.

“The information that we have suggests that this was defensive behavior, and it’s completely normal and natural for grizzly bears,” said Morgan Jacobsen with Montana Fish, Wildlife and Parks. “We don’t know for sure because we have no witnesses and we haven’t recovered a bear.”

Traps made from metal culverts and baited with meat were placed around the attack site over three nights with no success.

Game wardens will continue patrolling the area for at least another week as a precaution, Jacobsen said. National forest lands surrounding the site were ordered closed until Aug. 25 barring further notice.

Her mother, Janet Adamson, said her daughter — a former teacher from Kansas who left education to backpack across part of the U.S. and later wrote a book about her experiences — “died doing what she loved.”

“Every morning she’d get up early and she’d walk, hike or run. Every morning, she just was almost in heaven,” Janet Adamson told ABC’s “Good Morning America.”

The attack occurred along a trail used by hikers, horseback riders and off-road vehicles about 8 miles from West Yellowstone, a busy gateway community for the national park.

Amie Adamson did not have bear spray — a deterrent wildlife experts recommend people carry in areas frequented by grizzly bears.

A hiker found her body around 8 a.m. July 22.

The cause of death was excessive blood loss caused by a bear mauling, the coroner’s office said.