Updated

The parents of a missing San Diego girl who vanished from her bedroom more than a week ago offered a $25,000 reward Monday for information leading to her return.

Brenda and Damon van Dam said they hoped the offer would help sustain national attention on the case and lead to a breakthrough in the investigation.

"We're hoping and praying that this will motivate someone to come forward," Brenda van Dam told reporters outside their home. "Somebody out there knows something they're not talking about."

The family has not seen 7-year-old Danielle since Damon van Dam put her to bed on Feb. 1. She was discovered missing the next morning. Police believe she was abducted.

The couple said the reward money would come from their family's resources.

Over the weekend, a local radio station helped raised thousands of dollars for the search effort.

A man who offered early on to pay $10,000 for information leading to Danielle's return has acknowledged there is no money on hand to cover the reward.

Douglas Pierce, founder of the Millennium Children's Fund, said he could call on underwriters who support his organization if he needed to make good on the offer. Pierce reported no income and no expenses for the 2000 tax year on a federal tax form.

Over the weekend, hundreds of volunteers searched a 25-mile radius around the van Dam family home in the suburb of Sabre Springs for the second-grade girl. Teams of 10 carried orange tape, ready to mark any evidence they discovered. None was found, said Jody Maes of the newly formed Danielle Recovery Center, which has been assisted by the Texas-based Laura Recovery Center Foundation.

Only two search teams were dispatched Monday as the search went into its second week and volunteers returned to their day jobs.

The van Dams thanked the volunteers and renewed their call for more help. The couple said they prayed nightly with their sons for Danielle's safe return. "It gets harder everyday," Brenda van Dam said. "We're very emotionally drained."

"What we're doing is keeping in our minds that Danielle is alive and that she is coming home. That keeps us strong."

Signs of support remained hung throughout their neat suburban neighborhood. One banner, posted at a park that serves as a school bus stop, read "Hurry home Danielle. We miss you."

Danielle's disappearance has sparked intense media attention and the case was featured Saturday night on the crime-fighting show America's Most Wanted.

There have been no arrests.

Investigators have seized a motor home and property belonging to a neighbor of the van Dams, David Westerfield. The 49-year-old engineer has hired a criminal attorney and allowed police to search his home.