Relatives of 59-year-old John Wallace told ABC that he'd told his wife in a voicemail last week that "being in Yellowstone was like being in heaven."
Wallace's body was found Friday along the Mary Mountain Trail where he had been hiking. Hikers found his body by itself, surrounded by bear tracks. An autopsy concluded he died from injuries sustained in a bear attack.
"We're still trying to piece it together from the evidence that's on site in terms of what were the circumstances that led to the attack," Park Superintendent Dan Wenk told ABC News.
Wildlife agents are now trying to capture the bear. On Monday, they began setting traps, and they plan to kill the animal if they can establish through DNA analysis that it was the same bear that killed Wallace.
Wallace's death is the second fatal bear attack this summer at the famed park.
Brian Matayoshi was killed by a female bear in July while hiking along the popular Wapiti Lake Trail with his wife, who was forced to watch helplessly as her husband was attacked.
Matayoshi's killing occurred eight miles away from where Wallace's body was found Friday, but officials do not believe the same bear was involved in both attacks.
The female bear that killed Matayoshi was not killed because park officials said the sow was only defending its cubs and had not threatened humans before.
Park officials believe Matayoshi, 57, of California, disturbed a grizzly sow and her cubs while hiking with his wife.
When the couple spotted the bear, they turned and walked away. But when they looked back at the bear, they saw it was running toward them. The bear attacked Matayoshi as the couple attempted to flee.
In Wallace's case, there was too little information to know if his killing resulted from a defensive attack or not, so park officials decided to "err on the safe side of caution" in hunting the bear, Wenk said.
There were no signs of cubs in the area where Wallace was killed.
There are more than 600 bears in the greater Yellowstone area. The two maulings this summer, however, are just the first and second to occur inside the popular Yellowstone National Park in 25 years.
The Mary Mountain Trail, where Wallace's body was found, is a backcountry area known for its high population of bears. The trail is closed from March to June because it passes through an area frequented by grizzlies feeding on the carcasses of bison that died over the winter, park officials told the Associated Press.
Wallace, whose family said was an experienced hiker, entered the park alone last Wednesday and pitched a tent in a developed campground, according to Wenk. Authorities said he was likely killed Wednesday or Thursday.
A pack found alongside Wallace's body contained a snack bar, left untouched by the grizzly bear. No containers of pepper or bear spray were found in his pack, something wildlife experts warn against traveling without in bear-infested areas like Yosemite.
"We recommend people carry bear pepper sprays," wildlife biologist Kerry Gunther told ABC. "It gives people a lot of the confidence to stand their ground."
The Associated Press contributed to this report.