Thomas Fitzgerald never knew what hit him.

One minute he was riding home from his night-shift job and stopping his bike at Broad and South Streets to watch a mob scene that appeared to be getting out of control.

The next, he told a Philadelphia judge yesterday, he was waking up four days later from a medically induced coma, with his hearing impaired and his memory scrambled.

Two other witnesses yesterday helped piece together Fitzgerald's lost minutes as they described how, about 11:30 p.m. May 30, the 53-year-old bicyclist was set upon by eight young males, beaten, and left unconscious and in the middle of a violent seizure.

As a result of their testimony, Stephen Lyde, 21, was held for trial on assault, riot, conspiracy, theft, and other charges in what police described as an attack by a "flash mob" convened by teens and young adults through texting and online social messaging sites.

Lyde, of West Philadelphia, was the first of three people arrested in what police say was a rampage by more than 100 who blocked traffic, pounded on cars, stole merchandise, and assaulted several people.

The incident, and several similar ones in the weeks before, led to an increased police presence along the South Street corridor on weekend nights.

None of those called to testify by Assistant District Attorney Jennifer Mitrick told of having seen Lyde strike Fitzgerald.

Only one identified Lyde as having been at the scene. Erin Houdeshell said Lyde was one of five to seven men who stood around Fitzgerald while he had a seizure on the hood of a car.

"He said, 'Yo, look at his head,' " Houdeshell testified, referring to Lyde watching Fitzgerald's head twitch and bounce on the car's hood. "He seemed kind of entertained by the situation."

Houdeshell, who said she was a few feet from the victim, seated in her car that was stopped by the mob, testified she did not see Lyde strike Fitzgerald.

But, under questioning by Lyde's public defender Christopher Angelo, Houdeshell insisted she recognized Lyde at the scene: "I heard it. His mouth was moving, so I can say he said it."

Sharon Frohlick testified that she saw a man grab the strap of Fitzgerald's backpack and yank him from his bike.

Frohlick said the assailant threw Fitzgerald on the hood of a parked car and punched him in the face. Seven or eight others joined in, punching and kicking him as he slid to the ground while other spectators cheered.

"It looked like out of a movie," Frohlick added. "It was insane."

Frohlick, however, said she could not identify Lyde as Fitzgerald's assailant or even say he was at the scene.

Lyde was put near the scene by a surveillance video camera inside a Sunoco convenience store at Broad and Catharine Streets.

Lyde, well over 6 feet tall and dressed in a distinctive plaid shirt, is seen walking right by and glancing at the camera, one of a large group of young people who rush and ransack the store.

Mitrick said the store was damaged and lost products with a retail value of $6,598.

Lyde was also linked to the events after police learned Fitzgerald's ATM and credit cards were being used while he was hospitalized in a coma.

Philadelphia Police Detective Frank Straup testified that Lyde was arrested on the front steps of a house in the 5900 block of Osage Avenue, waiting for a delivery of clothing bought online from Neiman Marcus using Fitzgerald's credit card.

U.S. Postal Inspector Robert Bankhead, who participated in the sting, said Lyde allegedly gave a false name and said he was authorized to accept packages for Fitzgerald, whom he said was an uncle.

Lyde remains in custody after failing to post $100,000 bail.

According to Mitrick, one other adult is awaiting trial for a different assault on May 30, and a juvenile has pleaded guilty to helping Lyde in the alleged credit-card fraud.

Contact staff writer Joseph A. Slobodzian at 215-854-2985 or jslobodzian@phillynews.com.