A former policeman in Long Island, N.Y., and a former Drug Enforcement Administration agent, Brennan was fascinated by the mystery surrounding the case and convinced Foote to share information.
"I knew there might be a little reluctance to share any information with me," Brennan said. "I said 'Alan, I'm a good investigator. I'm not going to mess this up on you -- just let me run with it for you.'"
One of the first things Foote shared was the DNA results on the two preliminary suspects. There was no match and both Perez and Dimouleas were exonerated.
"I knew that the answer to the mystery had to be in those surveillance tapes somewhere," Brennan said. "You had to watch each and every frame on every video."
Slowly but surely, Brennan eliminated every suspect -- everybody but one.
"On the video, she goes out of the hotel early in the morning," Brennan said. "When she comes back about a half-hour later, there's a big, large, black man standing with her, and she just has a quick conversation with him. They get onto the elevator together."
The man can be seen entering the elevator with Budnytska at 3:41 a.m., then exiting the hotel with a suitcase at 5:28 a.m. But Brennan thought there was something strange about the way the suspect gave the suitcase a strange extra tug to get it loose from a gap in the elevator floor as he was leaving.
"I've done this, and you've done this countless times coming out of an elevator: Did you ever get it stuck so bad that you had to yank on it like that?" asked Brennan. "A light bulb went off and I said, 'This is the guy, and she's in that suitcase.'"
Brennan's theory: The man attacked Budnytska sometime after they entered the elevator together, dragged her body out of the hotel in the suitcase, drove off with her, dumped her body at the cul-de-sac and then returned.
Searching for clues to the man's identity on the security tapes, Brennan noticed that he frequently was accompanied by another man who had the word "Verado" written on the back of his t-shirt.
An Internet search turned up a hit.
"It showed that Mercury Marine made a brand new outboard engine by the name of Verado," Brennan said. "I said, 'Bingo, they're working at a boat show.'"
The Miami Boat Show was held the week of the crime, and Mercury was a major exhibitor, but none of the company's employees stayed at the Airport Regency.
Brennan discovered that the only shirts given out during the boat show were to food court employees working for a company named Centerplate, but the company runs concessions at events across the country and couldn't confirm if any employees stayed at the Regency.
About two weeks later, Brennan got a call: Someone remembered a man at one of the company's locations in New Orleans who matched the description, who'd been hired for the boat show out of the New Orleans area.
Luckily for Brennan, he had an in with the New Orleans police -- an old friend, Capt. Ernest Demma.
Brennan asked for Demma's help finding any information on his suspect, and soon confirmed that the mystery man was working at the Superdome when Hurricane Katrina hit.
"We were able to put the name with the body and come up with a hard description on the person he was looking for," said Demma.
The man's name was Michael Lee Jones.