SUNRISE, Fla. -- Investigators in South Florida are trying to find a 22-year-old woman from New York City who vanished more than two weeks ago.

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Police are desperate for a substantial lead in this case. Veteran investigators said they are holding out hope that Stepha Henry is still alive.

Henry came to South Florida as a birthday present to her 16-year-old sister, Shola, who traveled with her.

Shola spoke for the first time about her sister's disappearance Wednesday.

"As the time goes by, I really feel worse every time another day goes by," she said. "I keep on thinking she's calling me and all that. But I know she will come back home."

It has been 16 days since anyone has seen Henry. She rode to Peppers nightclub in Sunrise in a dark-colored Acura Integra the night she disappeared. Police have spoken to the driver, but investigators can't find the car.

Miami-Dade police found a car submerged in a canal on Tuesday. They hoped it was the dark-colored Acura Integra, but it was another false lead.

"We feel there's foul play involved," Cmdr. Linda O'Brien of the Miami-Dade Police Department said. "She's a responsible young lady, very bright. We just seem to think there was probably foul play involved."

Her parents have gone to the Peppers club, put up posters and urged anyone who knows something to call police. Her mother said every night she has the same nightmare -- that someone is holding her daughter against her will.

"Stepha, if you're looking on, I want you to know that I love you very much, and I will not stop until I find you," Sylvia Henry, Stepha's mother, said. "Your whole family is praying and looking for you."

Someone checked Stepha's voicemail at 4:13 a.m. the day she disappeared. Since then, the phone has been turned off.

Anyone with information about her disappearance is asked to call Crimestoppers at 305-471-TIPS.