A 10th-grader at the Bronx High School of Science, one of the city’s elite public schools, died early Saturday of a drug overdose, his friends and family said.

The boy, Lewis Dvorkin, 15, was pronounced dead at 5:15 a.m. September 25 at Lenox Hill Hospital. Although the medical examiner was still performing tissue and toxicology tests, people who knew him said Lewis – a fun-loving, guitar-playing, curly-haired boy – died after a heroin overdose at his East 86th Street apartment.

“Sometimes smart people make big mistakes. That’s apparently what happened,” Lewis’s grandfather, Gerald Dvorkin, said in a telephone interview.

“He’s a very sweet, intelligent, caring person, and this is just an unfortunate thing,” Mr. Dvorkin said. “He had his whole life before him, and he was prepared to do whatever it takes to make a decent life for himself, I hope.”

Mr. Dvorkin said the family is “devastated” by the death, and he hopes “kids will learn something from this.”

Lewis grew up on the Upper East Side, where he attended one of the city’s top public elementary schools, P.S. 6, and then the East Side Middle School before starting at Bronx Science in ninth grade. Lewis’s close friends learned early Saturday about what happened to him. Other friends and schoolmates found out during first period Monday, when the principal, Valerie Reidy, announced it on the school’s loudspeaker system. Ms. Reidy did not return a call from The New York Sun.

The skinny, blue-eyed teenager was known for his sense of humor, his purple Converse sneakers, and the graffiti tag he scrawled across the Upper East Side.

In honor of the graffiti, one of his friends, Elissa Mopper, is organizing a petition to create a Lewis-inspired mural at Bronx Science.

They say his favorite band was Leftover Crack and he dreamed of starting a band of his own. They say they walked beside Lewis in an AIDS walk and pedaled beside him in Critical Mass, the bicycle advocacy ride.

Friends he met in middle school and his newer friends from high school also said Lewis struggled through his first year at Bronx Science, often hanging out on the grassy hill across from school instead of attending class, and winding up in summer school after failing a few courses.

But they said he had plans this year to turn himself around.

One friend, who attended summer school with Lewis, said: “He had every intention of doing a lot better this year. …He didn’t want to disappoint his mom. He loved his mom.”

Although teenagers who spent time with Lewis said they were shocked and saddened by their friend’s death, they acknowledged that he had a problem with drugs. They said he had tried a wide range of drugs, from marijuana to opium to heroin.

“He’s done lots of drugs in his life,” one friend said, “and it just caught up with him.”

Spokesman for the New York Police Department declined to say whether they were investigating the circumstances of Lewis’s death.

Some of his classmates said going to a school like Bronx Science, which boasts among its graduates five Nobel Prize winners and five Pulitzer Prize winners, doesn’t confer immunity from drugs.

“I don’t think this school makes a difference,” Greg Horen, 15, said.

Another 15-year-old, Jillian Dunne, said, “It could be anywhere.”

A former guidance counselor at the school, Livia Sclar, said when she first took the Bronx Science job she was surprised that children could purchase drugs in the school hallways or at Harris Field across the street. She said she was also surprised that some parents apparently allowed their children to attend parties where there were drugs and alcohol.

“I think that it’s widespread,” she said.

The special agent in charge of the New York office of the Drug Enforcement Administration, Anthony Placido, said that more and more New York City youngsters are using heroin. The reason, he said, is that it’s now being sold in a much purer form and can be snorted or smoked instead of injected into veins. Mr. Placido said the new, purer product is “every bit as dangerous” and “highly addictive.”

He said he’s “not surprised” that a Bronx Science student was struck down by the drug.

“Drug addiction and the consequences of drugs don’t make any distinction between race, ethnicity, social class. It destroys equally across the board,” the DEA official said. “Kids in good schools, people in good families … they all fall victim.”

Friends say they have learned some lessons from Lewis – sort of.

One, who spoke of having experimented with heroin, said, “I would never shoot up after this. I don’t want this to happen to me, and I don’t want Lewis to have died in vain, for no purpose.”

Another teenager said he feels “obligated to do a lot better in school,” to undo the reputation Lewis and his friends earned as lazy students. “I feel I have to do better for both of us,” he said.

Lewis’s funeral service was held Monday. Hundreds of friends and family members attended. He is survived by his mother, Carole Robinson, his father, Stephen Dvorkin, and his brother, Nathan Dvorkin, a high school senior, with whom Lewis was very close.