Burton, who dresses and identifies himself as a woman named Peaches, according to acquaintances, was arrested Tuesday. Cops said they found the 22-year-old suspect walking with a man near 12th and Spruce streets, carrying some of Brady's belongings.
Bob Geary, a longtime friend who attended Penn State with Brady, was among those reeling from the unexpected twist.
"It turns out to be a transgendered with 36 arrests. How much more horrific could it be than that?" said Geary, who lives in Tennessee.
"If you would have told me a month ago that this would have happened . . . that's not the Pat Brady I know. I don't think any of us knew the Pat Brady that died there that night.
"Nobody knew that Pat Brady, but we're just going to hold onto the Pat Brady that we know and love."
Brady, an information-technology specialist who worked at Thomas Jefferson University Hospital, checked into the Omni late on Oct. 29.
Friends said earlier this week that Brady frequently stayed at hotels because of his work. A.J. Williams, the general manager at Omni, confirmed that Brady had stayed at the hotel several times.
So nothing seemed out of the ordinary until the following day, when Brady never made it to the Thorndale home he shared with his wife, Suzanne, and their 9-year-old daughter.
Shortly before 10:20 a.m., a small fire broke out in Brady's eighth-floor hotel room. Firefighters extinguished the blaze in a matter of minutes, then made the grim discovery.
Brady had suffered "obvious" head and body injuries, and an autopsy later determined that he had been strangled, said Homicide Capt. James Clark.
"Someone obviously set fire to the room to cover his tracks," Clark said.
Detectives used the hotel's security-surveillance system to help identify Peaches; cameras caught her entering the hotel overnight, Clark said.
Authorities say Brady let the prostitute into his room, but investigators are unsure what happened immediately afterward.
"We know there was an extremely physical altercation [in which Brady was] beaten, strangled and robbed," Clark said.
At least one guest heard the struggle, Clark said; it's unclear whether that guest reported it to anyone.
Williams said that several hotel staffers encountered Peaches in the hotel that night, and were left shaken and upset by the incident, as were some guests.
"We had to assure guests that this was the result of an encounter that was arranged by two individuals, and not some random act," Williams said.
When police arrested Peaches on Tuesday night in Center City, it didn't take long for cops to realize that they probably had the right person: She was carrying Brady's cell phone, identification and credit cards, Clark said. Detectives later determined the suspect had used Brady's credit cards to make several purchases, Clark added.
Though just 22, Peaches has been arrested 36 times in the past five years in Philadelphia, mostly for loitering and obstructing the highway - charges typically associated with prostitution, according to criminal records.
Prosecuting prostitutes - even those involved in violent encounters - often proves to be difficult, noted Temple University criminologist Jerry Ratcliffe.
"People who are victimized don't report anything to police because of shame and fear - fear of arrest, and fear that their activities will become known to friends and family," he said.
The reasons a person with a milelong criminal record like Peaches' was able to remain free on the streets mean little now to those grieving over Brady's death.
There are other things to focus on, like his burial tomorrow at the Holy Sepulchre Cemetery in Cheltenham, across the street from the city line.
Beyond that, there is only pain and questions, endless questions.
"I'll always love Pat Brady. I'll miss him for the rest of my life," said Geary, his old friend.
"Whatever he was into, I'm certainly not going to sit here and judge any of that.
"Whatever the circumstances surrounding his death, it shouldn't tarnish the rest of his life. It shouldn't tarnish his family and the good he did."