The U.S. Secret Service arrested an 81-year-old Wisconsin man who allegedly made threats to kill President Barack Obama in a Richland Center post office.

Elwyn Nels Fossedal, 81, was charged Thursday with making threats against the president of the United States, according to federal court documents released Friday.

According to an affidavit, Fossedal was at the post office in Richland Center, Wisc., in October when he said, “If President Obama was here I would shoot him and kill him right now.”

Fossedal was interviewed Oct. 16 by Secret Service agents, who said the 81-year-old Wisconsin resident “would not recant the … threat made towards the president and repeated the threat using different words. He also made a number of additional threats towards the president.”

During their investigation, federal authorities learned that Fossedal’s wife of 57 years died recently, and investigators believed Fossedal “was replacing his grief of her loss with anger.” The investigation also revealed that Fossedal “is proficient in the use of various firearms,” according to the affidavit.

The Secret Service agent who wrote the affidavit said “there is probable cause to believe Elwyn Fossedal did knowingly threaten the president of the United States.”

Fossedal appeared in federal court on Friday for his initial appearance. Court records showed the appearance lasted 15 minutes and Fossedal’s choice of attorney was approved.

According to the Smoking Gun, the 81-year-old may subscribe to the “birther” movement idea that Obama was not born in the U.S. The website also found that Fossedal is a fan of conservative radio talk show host Rush Limbaugh, who urged that Obama be impeached over the Affordable Care Act.