Martha Heredia was arrested late Wednesday as she was about to board a plane to New York, said Frank Duran, the National Drug Control Agency's director for the city of Santiago.
He said police found 2.9 pounds (1.3 kilograms) of heroin in the heels of three pairs of shoes packed in her suitcase. Police also ordered Heredia to undergo X-ray tests to determine whether she had any drugs hidden inside her body, but none were found.
Duran said police are interrogating Heredia to determine whether she was working as a mule for a drug-trafficking organization.
Prosecutor Luisa Liranzo said Heredia does not yet have an attorney. If found guilty, she could face more than 10 years in prison.
The 22-year-old had become a star in the Dominican Republic after she won the final "Latin American Idol" contest in 2009. The show, which ran for three years, was a Spanish-language version of the popular British "Idols" franchise.
On the night Heredia vied for the title, thousands of Dominicans gathered in public plazas to watch her sing on huge TV screens, and then-President Leonel Fernandez urged Dominicans to vote for her.
The country was paralyzed as Dominicans watched the show, prompting Fernandez to quip, "It was said the country came under curfew without the need of a presidential decree."
Miguel Vargas, president of the main opposition party at the time, had donated thousands of prepaid phone cards the night of the final contest so citizens could vote for their compatriot.
"Martha's tenacity and creative capacity are an example, and the least we can do is support her efforts," Vargas said at the time.
Dozens of fans greeted Heredia when she returned to the Dominican Republic after her win, and Fernandez invited her to the National Palace. In February 2010, he gave her the National Youth Award.
"The politicians are lucky you're not running for president because you would beat them all," he said at the time.
But Heredia, nicknamed "La Baby" because of her penchant for calling people "baby", disappeared shortly after all the fanfare, drawing speculations including that she was pregnant.
Then her name was back in the news for different reasons.
In December 2010, Heredia hit and killed a teenage Haitian boy with her car as he tried to cross a highway by foot. She was later ordered to pay his family some $275,000 as part of a lawsuit. The boy's relatives were angered that she did not meet with them to offer her condolences.
"That's not right," Elvys Vandredi, the victim's father, told a local TV station in a 2011 interview for a feature on Martha Heredia called "What happened to Martha Heredia?"
The TV station also featured an interview with Heredia, who said she granted the interview because she was tired of the rumors surrounding her disappearance from the local show business industry.
Heredia blamed her manager at the time for not scheduling concerts or public appearances.
"I need a person who barely sleeps, someone who is constantly connected to social media," she said.
In late 2011, she produced her first album titled "Lose or Win," which she recorded in Mexico under the Sony Music label. The first single did not do well.
Heredia's name disappeared once again and resurfaced last month when she filed a domestic violence complaint against her husband, Manuel Varet Marte, a hip-hop singer known as Vakero. He was ordered held in prison for three months as police investigate the case.
General Prosecutor Francisco Dominguez issued a statement saying Heredia's situation was unfortunate.
"It's very sad that young people who have so much promise, who were bestowed by life with all the grace in the world and an unquestionable talent, because of ambition, bad advice or simply to obtain money see themselves in situations like this," he said.
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