Yellowstone National Park staff killed a newborn bison after a visitor helped it cross a river, an apparent rescue effort that led the calf herd to reject the animal, park officials said Tuesday.

The calf had been separated from its mother when the herd crossed a river in a northern section of the park on Saturday, Yellowstone said in a news release.

As the calf struggled to cross the river, the man approached the animal and pushed it up the river toward a road, the statement said.

Visitors later saw the calf walking towards and following cars and people, according to the statement.

Park rangers repeatedly tried to reunite the calf with the herd, but the efforts failed, according to the statement, which notes that human interference can cause wildlife to reject their calves.

After failed reunification efforts, newborn was killed by park staff «Because it was abandoned by the herd and caused a dangerous situation by approaching cars and people along the road,» the statement said.

He release noted park regulations require visitors to stay at least 25 yards from all wildlife, including bison, elk and deer, and 100 yards from bears and wolves.

the park website has a page that explains why he doesn’t rescue animals after being injured or when separated from their mothers.

The park said law enforcement officers are seeking more information about the incident.

It is not clear if he could face possible criminal charges. A park spokesperson did not immediately respond to a request for comment.