Federal authorities say two men who escaped from a private Arizona prison and a woman thought to have helped them are believed to be in the area around Yellowstone National Park.

The U.S. Marshals Service says information has developed within the past two days that indicates Tracy Province, John McCluskey and Casslyn Welch may be hiding in portions of the park that span Montana and Wyoming.

Authorities say it's now believed Province has separated from McCluskey and Welch.

The manhunt intensified after forensic evidence linked at least one of the inmates to the killings of an Oklahoma couple in New Mexico earlier this week. The couple's badly burned skeletal remains were found in a charred camper on a ranch in Santa Rosa.

New Mexico State Police spokesman Peter Olson calls the search an "urgent situation" given the New Mexico slayings.