The reward announcement follows a 10-day search for the little girl with still no sign of the second-grader.
During the press conference, Danielle's father, Damon said, "Our daughter's missing and we had nothing to do with it."
The mother, Brenda van Dam, said, "We pray for Danielle each night." "We're very emotionally drained," she added.
Damon and Brenda told authorities they last saw their eldest child when her father put her to bed about 10 p.m. on Feb. 1. They said they realized she was missing about 9 a.m. the next morning. Volunteers gathered Saturday at a motel near the van Dam home and searched a 25-square-mile area near Sabre Springs as well as a desert area in the Imperial Valley, Calif.
Searchers went to the desert because that's where a neighbor who police have focused on said he spent Feb. 2 and 3, when the girl disappeared.
The neighbor, David A. Westerfield, apparently took his recreational vehicle to an area near Glamis on the same morning the girl was reported missing.
While continuing to label Westerfield, 50, A "potential suspect" in Danielle's disappearance, detectives have twice gone through his home with service dogs. He lives lives two houses from the van Dams.
During those searches, officers carted off boxes and bags full of household items. In addition, police impounded Westerfield's sport utility vehicle and the motor home he took to the desert over the weekend.
Some of the items collected from Westerfield's home included child pornography, according to local news reports.
Westerfield (pictured, left) hired criminal defense attorney Steven Feldman, even though he has not been arrested or charged with any offense.
When reporters asked Westerfield outside his home last week if he knew where Danielle was, he shook his head, said no and walked inside.
Police have repeatedly said they do not consider the van Dams suspects in the girl's disappearance, which is officially considered a case of kidnapping, though they pointed out that no one has been completely ruled out.