ESCONDIDO, Calif. -- A search of a nearly drained pond in a city park turned up no clues today in the disappearance of Amber Dubois, who was 14 when she disappeared a year ago while walking to Escondido High School.

Investigators got a tip Thursday that last May, three girls found a black plastic bag and human hair at the edge of a pond at Kit Carson Park, said Escondido police Lt. Craig Carter.

The parents of Amber Dubios were contacted immediately. They have been searching ever since she vanished February 13th, 2009.

“You can't get off the rollercoaster. It won't stop. It goes on and on and no matter how much you scream or how much you cry and you want the ride to end, it's not ending,” said Dubois’ father, Maurice Dubois.

“I still think she's alive and being held somewhere,” said Dubois’ mother, Carrie McGonigle.

Detectives found a bag Thursday night, but it contained only mud and debris, Carter said. It was given to the FBI to analyze. "Detectives have concluded that no evidence of hair was present in or around the recovered bag," Carter said. "No other evidence was located as a result of the two-day search."

City public works crews worked pumps overnight to drain the pond down to three or four feet of water and remove thick stands of reeds.

The children's parents called in the tip after seeing news accounts of Chelsea King, 17, of Poway, whose body was found in a shallow grave on the shore of Lake Hodges, about two miles from Kit Carson Park.

Registered sex offender John Albert Gardner III, 30, was arrested Sunday in connection with King's death, and is being looked at as a possible suspect in other crimes, including Amber's disappearance.

"Now we wait for the next lead to come in," Carter said. "Nothing else came in this weekend. We have nothing new to pursue."

About 30 to 40 law enforcement officers, including the sheriff's reserve dive team and search and rescue volunteers, Escondido police, the San Diego Mountain Rescue Team and the FBI evidence response team began today's search in the murky water around 8 a.m. and called off the search about 2 p.m., Carter said.