Hughes and a buddy decided to spend the weekend at a Ritz-Carlton Hotel, which was down the street from a Sheraton where Hughes had been staying.
On Saturday, they went out for drinks. Hughes stayed out long after his pal called it quits and "got pretty wasted," Byrne said.
He stumbled back to his hotel about 3 a.m. Sunday and went to the wrong room on the wrong floor.
"He got confused. He was thinking about the room he stayed in at the Sheraton," Byrne said.
But Hughes, 42, didn't recognize his mistake. He told a hotel clerk that his key didn't work, and the clerk made him a new one - for a two-bedroom suite that happened to be inhabited that morning by a local family.
The clerk has since resigned, according to the St. Louis Post-Dispatch.
"He went back up and opened the door. The chain was on, so he kicked in the door," Byrne said.
Hughes staggered into one of the bedrooms. A 9-year-old girl was sleeping quietly in one bed, while two 14-year-old girls were asleep in the other.
"He got undressed and got into bed with the 9-year-old and molested her," Byrne said.
"She woke up and told her mother. Her father chased him out."
Hughes was nabbed by security guards in the lobby of the hotel and later arrested by Clayton police.
He was charged with statutory sodomy and child molestion, and was still being held yesterday in Clayton on a $250,000 cash bond, Byrne said.
An Enterprise Rent-a-Car spokeswoman said the company has suspended Hughes, pending the outcome of the criminal investigation.
Hughes' neighbors on Church Street near Bullock Avenue were stunned by the news of his arrest.
"Dan's lived here for a couple years. We all know him. He's very helpful, very sociable," said longtime resident Gerry Keenan.
"The more I think about this, it sounds too far out of character for him. We're all shocked."