The father of a missing South Carolina woman issued an urgent plea Monday for the public's help in locating his daughter, a day after hundreds of volunteers scoured the area in search of the 20-year-old woman.

Authorities and volunteers combed woods and ponds in Horry County, S.C., over the weekend looking for any sign of Heather Elvis, of Myrtle Beach. Nearly 300 people searched for 10 hours on Saturday for the young woman who was last seen at about 2:30 a.m. on Dec. 17.

"It’s a living nightmare," Elvis' father, Terry, told FoxNews.com on Monday. "I can't beg enough for information. If you've seen anything, if you've heard anything, if you have a friend, family member or acquaintance who acted differently on that day, I beg you to come forward."

"Any information -- as trivial as it may seem -- helps us," he said. "This could be anybody's child."

Heather Elvis was last heard from around 3 a.m. Dec. 17 after she went on a date, according to her family. Her car was found abandoned at a boat landing Dec. 18 in Horry County.

A source close to the case said the young man whom Heather met on the date is not considered a suspect. Her cellphone has not been located, the source said.

Lt. Robert Kegler of the Horry County Police Department told FoxNews.com that "several people" are being interviewed in connection with the disappearance. "Some are cooperative, some are not," he said.

Investigators are poring over new leads on Monday and the case remains "very active," Kegler said.

Authorities searching for Elvis last week discovered the skeletal remains of a male in his 20's. The initial discovery had raised questions that the bones could belong to 17-year-old Brittanee Drexel, who was last seen in 2009. Drexel, a high school junior from the Rochester area, went with friends and without her mother's permission to Myrtle Beach on April 23, 2009. Authorities have long said they suspect Drexel is dead, but exhaustive searches for the teenager have never turned up her remains.

A $20,000 reward is being offered for any information leading to Heather Elvis. Anyone with information on the case is urged to call investigators at 843-915-TIPS.