A botanist who died from a grizzly mauling hours after the animal was caught, tranquilized and released by researchers east of Yellowstone knew about the capture before he entered the area, a friend said.

Erwin Frank Evert, 70, died Thursday when a male grizzly bear attacked him near an Interagency Grizzly Bear Study Team site in the Kitty Creek drainage, about six miles outside the East Entrance of Yellowstone National Park. He was known as an expert on vascular plants of the region and a scientist who used his legs to conduct extensive field research.

Evert’s friend Chuck Neal, a wildlife ecologist and author of Grizzlies in the Mist, said Evert contacted him before the incident to ask about the grizzly bear capture and the closure associated with it.

“He knew the [closure] sign was there,” Neal said. “He asked me what I thought about it. I said, ‘just don’t go anywhere near it.’”

Despite the warnings, Neal said Evert apparently took a circular route up a ridge to the east of his cabin, walked south along that ridge and came down into the drainage.

“What he’s doing is walking toward the trap site,” Neal said. “He knew it; why he did it, nobody can fully explain.”

Neal described Evert as an experienced outdoorsman who knew about grizzly behavior.

“Erv has read [Grizzlies in the Mist],” he said. “He knew what to do and what not to do. He knew he shouldn’t be there. It’s a terrible tragedy for both man and bear.”

Neal told his story as officials and researchers with the Interagency Grizzly Bear Study Team, the Wyoming Game and Fish Department and the U.S. Fish and Wildlife Service have kept mum on many details surrounding the incident, pending an investigation. For example, officials did not disclose the details of the area closure, how the bear behaved during the capture, what signs might have been up for how long, how long the area remained closed after the bear’s release and whether it was trapped or snared.

The bear had never been captured before, said Chris Servheen, grizzly bear recovery coordinator for the U.S. Fish and Wildlife Service. The bear was a young male, between 5 and 10 years old, and roughly 400 pounds, he said.

Researchers will conduct a postmortem exam on the bear’s remains, which could determine whether the bear had some illness or condition that caused it to act aggressively, Servheen said.

“This bear didn’t have any distinguishing illnesses,” he said. “The bear had bite marks on him [from another bear], but you’d be hard pressed to find a male bear that didn’t have bite marks on him.”

When asked if the tranquilizer used on the bear might have caused aggression, Servheen said such a reaction was highly unlikely. Researchers used the drug Telazol, a short-acting anesthetic and muscle relaxant that is commonly used by veterinarians.

Researchers stopped using Sernalyn, also known as PCP, to drug bears decades ago, Servheen said. While some have suggested that Sernalyn causes aggression in bears, Interagency Grizzly Bear Study Team coordinator Chuck Schwartz said “there’s no empirical data to support those statements.”

Just how an animal reacts as it wakes up from the Telazol depends on the individual animal, Schwartz said. “In most circumstances ... it’s a very predictable process,” he said. “[It starts with] swaying of the head, and movement in front legs. Then they begin to get the use of back legs. In most cases they leave the area. Typically they go to sleep and they metabolize the drug out of their system.”

While Schwartz wouldn’t comment on the closure associated with Evert’s death, he did describe a protocol for closures during bear captures. After getting permission from the land management agency, Schwartz said researchers will pick a site, set a trap or snare and then sign the area.

“We completely encircle the area [with signs],” he said. The radius of the closure depends on a number of factors, including terrain. The closures are typically far from roads and trails.

“The signs basically indicate that we’re doing grizzly bear research in the area, that it’s dangerous, and the area is closed,” he said.

Typically the signs will remain in place until the operation is complete, Schwartz said.

An investigation into the incident will determine whether researchers followed those procedures.

“If it’s possible, we want to learn from it to help minimize any possibility that we ever see an unfortunate circumstance like this again,” Schwartz said.

The capture experience might have made the bear more hostile toward humans, especially if the animal was still experiencing the effects of the Telazol, Neal said.

“My speculation is [that the bear] was somewhat groggy and could not hear or smell anything,” he said. “My thinking is the two came together nose-to-nose, face-to-face.”

Neal said he is frustrated by the lack of information from the agencies.

“What’s kind of quiet is what went on with that team,” he said. “The agencies have gone into a circle-the-wagons, cover-your-ass mode. I think they feel a little bit insecure at the moment.”

Evert was a unique combination of scientist and outdoorsman who traveled to remote locations in his quest for plant species, Neal said.

“[Evert] spent the last 40 years inventorying all the vascular plants in the Greater Yellowstone Area,” he said.

Evert’s book, Vascular Plants of the Greater Yellowstone Area, “is going to be his legacy.” Neal said. “It involved tremendous time and effort.

“He was obviously characterized by professional excellence,” Neal said. “No one can match ... his combination of botanical expertise and physical activity.”

Louisa Willcox, a wildlife advocate for the Natural Resources Defense Council, called Evert a “very, very interesting guy.”

“He was an incredible botanist who taught me a lot about plants,” she said. “It’s a really sad loss.”