A Yellowstone National Park visitor remained in critical condition at an Idaho burn center Monday and could face criminal charges, after falling into a thermal pool late Sunday, the Associated Press reported.

According to the AP, Cade Edmond Siemers, 48, told park rangers he was walking near Old Faithful Geyser without a flashlight when he tripped into a hot spring. Siemers, a U.S. citizen who had been living in India, was later airlifted to a burn center at the Eastern Idaho Regional Medical Center in Idaho Falls for treatment.

The National Park Service told NBC News after questioning Siemers, rangers suspected alcohol might have played a role in the incident. In addition to his shoe and hat, investigators who returned to the scene Monday found a beer can alongside footprints leading to and from the geyser.

Yellowstone National Park spokeswoman Morgan Warthin told the AP the water temperature at the pool where Siemers was injured measured almost 150 degrees Fahrenheit when it was tested in August. 

After reviewing the park service’s investigation results, the U.S. Attorney’s Office will determine after if criminal charges will be filed.

Siemers' incident occurred less than two weeks after two unidentified men were issued summons for "thermal trespassing" by the National Park Service for walking up to Old Faithful's edge.

Meanwhile, Gabriel Villalva, 27, of Greeley, Colorado, was arrested in September 2018, in Cheyenne, Wyoming, one week after he was suspected of the same offense.

Click here to learn more about Old Faithful Geyser.

The Associated Press contributed to this report.