A 22-year-old Utah man has been ordered to serve three years in federal prison for stalking his ex-girlfriend in Yellowstone National Park.

Jose Bradley Isaacson received the sentence during a Nov. 21 hearing in U.S. District Court in Cheyenne.

Following a months-long, off-and-on relationship, Isaacson and the woman broke up in early summer, charging documents say. But on June 19, while the woman was working at the park’s Old Faithful area, Isaacson sent a series of threatening messages that reportedly included comments about shooting her.

The woman contacted park rangers, showing them texts and recounting calls she’d received from Isaacson. During a ranger’s 17-minute meeting with the woman, charging documents say Isaacson tried calling his ex’s phone 10 times. He later demanded $2,000 from the woman to end the relationship, but after she sent the money, charging documents say Isaacson told her “it was never going to end.”

Yellowstone officials issued a “Be on the Lookout (BOLO)” for Isaacson and his vehicle. However, he apparently made it from his home in Logan, Utah, to the woman’s employee dormitory on the evening of June 21. Charging documents say he tried getting the woman to leave with him and grabbed her when she refused.

Isaacson then took her phone and fled, just before rangers arrived. The following morning, prosecutors say he stole an idling rental car from the Old Faithful Inn parking lot. He made it 65 miles before rangers in Grand Teton National Park punctured his tires. They took him into custody after a foot pursuit.

As part of a deal with the U.S. Attorney’s Office for the District of Wyoming, Isaacson pleaded guilty to a felony count of interstate stalking.

After Isaacson completes his three-year term of incarceration, he’ll need to serve three years of supervised release. During that time, U.S. District Judge Alan Johnson has barred Isaacson from having any contact with the victim, among other conditions.