The scion of the Busch beer dynasty spent Monday night in police custody.

Former Anheuser-Busch CEO August Busch IV was arrested in Swansea, Illinois, for allegedly trying to fly a helicopter while intoxicated, according to court documents. Prosecutors said they would wait for toxicology tests before deciding whether to file charges.

The events leading up to his detention began to unfold on Monday afternoon just before 1 p.m., when police responded to a report that a helicopter was landing in a parking lot "for an unknown reason," according to a statement from the Swansea Police Department. The helicopter was already on the ground when officers arrived, and the Federal Aviation Administration was called to investigate.

It is unclear if Busch was the pilot who landed the helicopter.

Around 8 p.m., police were dispatched to the scene again after a caller said a pilot returned to the aircraft and "appeared too intoxicated to take off."

The helicopter's rotors were spinning and the engine was revving up when a squad car arrived, the department said. Busch, who was identified as the pilot in court papers, was accompanied by a woman who identified herself as his wife.

After conducting a series of field sobriety tests, the officers arrested Busch and took him to the hospital for blood, urine and breath tests. He remained in custody until Tuesday afternoon, according to a statement from Swansea police.

A search of the helicopter yielded various prescription medications, a pepper spray gun and three loaded firearms. Busch, who told police he has a concealed carry license in Missouri, was also carrying a gun on his person.

"This is not your normal case that a street police officer handles," Swansea Police Chief Steve Johnson said in a statement. "The safety and security of the community, the pilot and the passenger were of the utmost concern."

Cam Wiggs was at work on Monday when he saw a helicopter land in the parking lot outside his office.

"One of the weirdest things I've seen," Wiggs told CNN. "It was definitely a shaky landing. I assumed it was an emergency landing because it was so shaky."

Anheuser-Busch declined to comment on the incident. The former executive is not currently affiliated with the company.

Busch could not be reached for comment.

Busch was named CEO of the American brewing behemoth in 2006. He was at the helm when Belgium's InBev crafted a takeover in 2008.

-- CNN's Amanda Jackson contributed reporting.