ST. AUGUSTINE, Fla. -

Police say the driver who hit and killed 15-year-old Haley Smith is still out there, but he or she may not even know they hit her.

Investigators say their search for the driver has gone cold as her family celebrates her 16th birthday.

It's been three weeks since Smith was hit and killed on Kenton Morrison Road. The driver never stopped. Investigators found the passenger side mirror from the car at the scene.

Police said it may have belonged to a small pickup truck that was seen driving on Holmes Boulevard the night of the crash.

On Saturday, dozens of family and friends gathered at the spot where Haley died, in honor of her birthday.memorial3

While the past few weeks have been hard, police said they remain committed to finding the person responsible and bringing them to justice.

"As I said before, we're not looking for revenge, we just want to know why and what happened and give our family some closure," said Jo-Lee Manning, Smith's mother. "Its overwhelming to see how many people she touched. They continue to reach out, support and help us look for the person who did this."

Smith's best friend, Brittany Szczepanik, said she considered Haley her twin sister because they shared the same birthday.

"Words cant describe the way I'm feeling now," Szczepanik said. "Whoever knows anything, please come forward. Me and my family, we don’t deserve to suffer like this. She is like my twin. The fact I don't have her hear today, it kills me."

Authorities have increase the reward for information on the crash.

Anyone with any information on this case is asked to call Crime Stoppers at 888-277-TIPS.