Shaun P. Matlock pulled on a helmet, climbed aboard a Yamaha sport bike a few miles west of Frederick and opened the throttle, roaring at high speed past hills and farms along a forlorn stretch of highway, toward West Virginia.

He wore only a T-shirt and shoes. He also wore two logos: The stickers, slapped on his helmet and his bike, bore the words "Holding It Big," the slogan of an upstart company in Baltimore that promotes extreme sports events and videos.

What Matlock thought lay at the end of that stretch of highway is unclear. Street cred? Fame? Money?

As the sports promoter filmed Matlock from a chase car and several friends watched last Sunday evening, Matlock and another rider, who also was partially clad, sped off. Matlock pulled up the bike's nose to perform a wheelie at high speed and lost control, careering off the highway into the rear of a parked tow truck, according to police and witness accounts.

Police arrived quickly. Minutes before, they had received reports of motorcyclists stunting for a movie camera. Matlock, 21, died on the spot.

Hundreds of friends have turned out for vigils at his favorite hangout, at the site of the accident and at a funeral home in Frederick. He was buried Friday.

Matlock's family blames his death in part on the American anything-for-fame mentality and a culture glutted with reality TV shows and over-the-top stunts glamorized by "Jackass: The Movie" and the discontinued MTV series that preceded it. They also want the message of their son's death to spread to the small but fast-growing world of bikers who illegally perform death-defying stunts on highways and fill the Internet with proof of their fearlessness.

And they want answers from Ben Meacham, 22, the entrepreneur who filmed the stunt for his company, Holding It Big Entertainment, according to Maryland State Police and a witness. Not long before the accident, Meacham took out a newspaper ad promoting his plans to film stunt riders in the Washington area for a movie, saying "a good documentary will change the perspective on reality."

"I think he was killed by a video camera," Ray Matlock, 58, said of his son. "It's the thrill of publicity. It's the thrill of being on the Web."

The circumstances surrounding the crash are still under investigation by police and the Frederick County state's attorney.

State police recovered a videotape from Meacham, Cpl. Jay Robinson said. "He was definitely videotaping what the gentlemen were doing on the bikes," Robinson said. He also said Meacham told them he erased that portion of the video.

"There's really no law against filming. The problem might be erasing it, because then you might be destroying evidence," Robinson said. He said a decision on whether to charge Meacham is up to State's Attorney Scott L. Rolle.

"The whole situation is under investigation to see if there was any criminal wrongdoing or traffic offenses committed by anybody involved," Rolle said.

Efforts to reach Meacham through the telephone number and e-mail address listed on his Web site were unsuccessful. One of his business addresses belongs to Triangle Motors, a Frederick auto dealership owned by his father, Tom. But a request for an interview through his father also was unanswered. "I'm not sure what I can tell you," Tom Meacham said. "You really ought to talk to him."

Phone messages left for the second rider, Brandon Edwards, 21, of Ijamsville, were not returned.

Rolle focused attention on a popular culture that rewards people for performing stunts no matter how gross, stupid or dangerous. Not long ago, he said, an 18-year-old Frederick County man was charged with beating up a high school football player while other young men filmed it.

"There's so much of these reality shows on TV, and shows like 'Punk'd' and 'Jackass,' " Rolle said. "They can say, 'Don't try this at home,' as much as they want, but you can't tell me a 16-year-old is not going to try this at home. They don't care whether it's dangerous. . . . If it gets them in the spotlight for a time, they'll do it."

Matlock's death also offers a look at a fast-growing subculture of daredevils who perform heart-stopping acrobatics on sport bikes. Long popular in Europe, the movement has caught fire in the United States in the past five years. The aim is simple: Do things no one has ever seen. Then put it on the Web.

Known as "Ninja bikes" and "bullet bikes," sport bikes are streamlined machines that allow the drivers to hit high speeds while riding the bikes belly down, head first and low to the street.

"It's a relatively recent subculture . . . that still tends to stay to itself," said Jason Colon, editor of Cycle World's annual Sport Bike special edition. "There's a lot of guys in Middle America. A lot of guys coming out of places where there's no winding canyons."

Of course, motorcycle stunts are almost as old as the internal combustion engine, and Evel Knievel became famous nationwide for his bone-crunching motorcycle jumps in the 1970s. But now minicams and the Web have made it possible for almost any fearless soul to demonstrate courage -- or foolishness -- to the entire world.

Trawl the Web and you'll find promotional sites for stunt teams with names such as Starboyz, Unsane Ryderz and Scooter Trash. Some talk about their worst spills and injuries. Others sell T-shirts with logos. Many hawk videos of their wildest tricks.

Almost every Web site warns that the stunts are dangerous or urges amateurs not to perform them on the highway. But several also invite amateurs to submit footage of their hair-raising tricks. Participants are mostly men in their twenties, though some men in their forties are doing stunts and even a few women, Colon said.

But Colon also said the activities are moving into the mainstream, with promoters trying to take stunting off the streets and onto drag strips and racetracks.

"It keeps stepping up and reaching higher. It's all about going to the next level," said Greg Sunday, 26, a member of KC's Most Wanted stunt team in Kansas City, Kan. Sunday's first sport bike was a Suzuki Katana 600 cc. He started riding when he was 16 years old. He also started stunting on the street. About three years ago, he and his brother Grant and two other young men formed the stunt team, performing at local drag strips and tracks.

Now they go on the road, and there are big events such as Bike Week and Stunt Wars, both of which are held in Florida.

"It used to be all about doing 70-, 80-, 90-mile-per-hour wheelies. But it's not that fun anymore," Sunday said. "I don't do them anymore. Too dangerous."

A shrine has grown at Matlock's crash site. A red Ron Jon surf shirt was taped to the guardrail, and people have scrawled farewells: "R.I.P.," "Showboys 4 Ever" and "I will never forget you -- hold it big, love Ashley & Cameron." A photo shows Matlock sitting near a flag from the Grateful Dead. There is a decal from Holding It Big Entertainment.

Brenton Heller, 19, of Frederick said he looked up to Matlock. "He was so kind and caring. He just loved his friends," Heller said.

Sitting on the hood of a 1987 Oldsmobile that his son restored, Ray Matlock talked so quietly that it was hard to hear the fury his words imparted. During an interview the night before his son's funeral, Matlock, manager of a FedEx Kinko's, said that when his son's friends ask what they can do, he challenges them to look him up next year and describe how his son's death changed their lives.

Ray Matlock described his son as a loving, high-spirited young man who had been fascinated with mechanical things since the days he played with Legos. Once, he proudly showed off his installation of video screens on the sun visors of a new Corvette.

He loved the beach and road trips. He once took off for Texas with nothing but $5 and a pack of cigarettes. And he liked thrills, or at least speed.

Shaun Matlock, who worked in an auto parts store, had borrowed the YZF750 Yamaha from a friend for about six months, his father said. But he also was watching videos of a stunt team practicing maneuvers, each member trying to one-up the others.

Ray Matlock said Brandon Edwards told him it was all about the camera.

"This kid will tell you they decided to do the most outrageous thing because they were being filmed," Matlock said.

Heller, who witnessed the accident from a car, said Matlock was going at least 80 mph when he crashed. The impact tore off his helmet and hurtled him through the air. Heller said he ran to his friend, attempted to revive him and cradled his head as he lay dying.

"It was just part of what he had suggested that he wanted to do," Heller said. "He was a man of courageous things. He always did crazy things. This time, he was just over-crazy."

Friends called Matlock's parents, who drove to the scene before police notified them. Trooper Robinson talked Ray Matlock out of walking down to where his son lay, saying it was not something a parent should see. Shaun Matlock's mother, Jolene, a nurse, collapsed when troopers told her that her son was dead.

Staff researcher Bobbye Pratt contributed to this report.

A shrine honors Shaun Matlock, who died after he lost control of his speeding cycle."I think he was killed by a video camera," Ray Matlock, 58, says of his son. ". . . It's the thrill of being on the Web."