AUSTIN, Texas - Tracey Crossett graduated high school early, had a new car, a new boyfriend and planned to study music in college.

She was 17 when her father found her dead at home on Easter Sunday, a needle lying next to her on the floor.

"Everything was going her way," Steve Crossett said. "She was a brilliant kid. A very outgoing kid ... This has been the worst experience of my life."

Thirty-four people have died so far this year in Travis County from a heroin overdose, up from 23 last year. Crossett was the youngest.

Authorities believe a particularly potent strain of heroin being smuggled into the United States and circulating on the streets of the Texas capital is partly to blame for the highest number of heroin deaths in Austin since 1992.

"We go through this periodically," said Austin Police Cmdr. Harold Piatt. "The heroin being sold on the street is too strong for some people to take and when you shoot it into your arm, it's too late."

For Tracey Crossett, that moment came on April 11.

A singer and bassist in a rock band, The Quicks, she had played a Saturday night gig in an Austin club, a show her father attended.

Around midnight, she arrived home in the affluent suburb of Lakeway. She went into a bathroom, fixed a hit in a syringe and shot up. Her father found her around 6 a.m.

"When you think of heroin users, you think of old men in a gutter, not a teenager. It was only six or seven months from the first time she used to when she died from it," he said.

Heroin's potency - and its potential lethal effect - depends on its purity.

Police say most of the heroin in the Austin area comes from Mexico and is known as "black tar" because of its sticky, hard consistency and dark color, which comes from the manufacturing process. Dealers "cut" the heroin - bulking it up to make more money - by mixing it with water-soluble products like powdered milk or chocolate, sugars or starches before it hits the street.

And it's cheap - a typical dose sells for about $20.

Steve Crossett said a toxicologist told him Tracey's fatal dose was from Mexico. But the overall rise in deaths suggests Austin may have an influx of stronger heroin from other parts of the world, said Jane Maxwell, a professor at the University of Texas' Center for Social Work Research.

Heroin from Mexico is typically regarded as the weakest; South American is the strongest, Maxwell said.

"It could be the Mexicans have come up with a new method of refining their heroin to make it purer," she said. "It could be some South American heroin has come in from the East Coast."

"If it's the South American heroin, we are going to see lots more overdoses," she said. "Experienced Austin black tar users will overdose because it's so strong."

Piatt said heroin samples from Austin have been sent to the Texas Department of Public Safety for testing but have not yet been returned.

Dennis Barkway, director of admissions at Austin Recovery, a nonprofit rehabilitation clinic, said he has not seen a rise in heroin-related admissions, which usually means the drug is readily available on the street and powerful. More people seek treatment when the supply can't meet demand or they can't get high off what they buy, Barkway said.

"When it dries up or there's bad stuff on the street," he said, "that's a good time to get clean."

Piatt said police have stepped up efforts to get the drug off the street, seizing almost 1,400 grams, about 3 pounds, compared to 37 grams last year.

Among the 34 deaths this year, 26 victims were 36 years old or older; the oldest was a 57-year-old woman.

Younger drug users are more likely to start with marijuana, crack and "designer" drugs like ecstasy before turning to the hard-core experience of shooting up heroin, Piatt said.

"In my experience, it's the drug of last resort," he said.

Maxwell disagreed, noting that heroin is now available in snortable and smokeable forms and often pushed to new users with the promise those forms are not addictive.

"There are many people who would never stick a needle in their arm but wouldn't think twice about smoking or snorting something," Barkway said. "Some (addicts) can be almost dead and say 'At least I don't use a needle.'"

Tracey Crossett first tried heroin when she snorted it at a party in 2003 because she was curious, her father said. She quickly moved to needles, he said.

In November, the family sent her to rehab for a month. She seemed to be doing well when she got out.

Four days before she died, she told an addict support group that she had been drug free for four months and had "never been happier."

"I'm sure she figured she could do this one more time," her father said. "One more time is all it took."