A neighbor of a 7-year-old girl abducted from her bedroom three weeks ago was arrested Friday after her blood was found on his clothing and in his motor home, police said. The girl was still missing.

David Westerfield, 49, was taken into custody for investigation of kidnapping in the disappearance of Danielle van Dam, who vanished in the middle of the night.

Police Chief David Bejarano said DNA tests confirmed the blood in his vehicle and on a piece of his clothing was the girl's.

"I can't stress enough how strong that link is," the chief said.

Westerfield's attorney, Steven Feldman, said he will likely ask a judge to impose a gag order on those involved in the case.

"We certainly intend to mount a vigorous defense but we don't wish to try the case in the media," he said.

Danielle was reported missing from her second-story bedroom the morning of Feb. 2 when her parents went to check on her.

Bejarano would not offer any details about what may have happened to the girl and would not discuss why she was kidnapped.

"We are very happy that police have made an arrest... But the fact still remains that we don't have our daughter. We still need to find Danielle," the girl's mother, Brenda van Dam, said outside the family home.

Search leaders made a renewed plea for more volunteers over the weekend.

Bejarano said police have no conclusive evidence on whether she is alive, but added, "As a father, I'm optimistic that at some point we will find Danielle."

Police have questioned Westerfield several times in the case. His sport utility vehicle, motor home and other property has been impounded.

Police said Friday that child pornography was found in his home.

Westerfield, a self-employed engineer and divorced father who lives two doors down, appeared calm as he was led into an unmarked police car.

Damon van Dam, the girl's father, has previously said that the family did not know Westerfield well.

"He's an acquaintance. He's not a friend," van Dam said. "We've seen him since we moved in. We wave to him. We say hello to him when we drive by."

Westerfield was transferred to San Diego County jail after questioning. He is expected to be arraigned Tuesday.

Westerfield has told reporters that he saw Brenda van Dam at a bar near their home the night before Danielle was reported missing. Westerfield also said he went away that weekend and later showed police the locations in the desert east of San Diego.

Danielle was last seen when Damon van Dam put her to bed about 10 p.m. on Feb. 1. He stayed home with Danielle and her two brothers while Brenda was at the bar.

Brenda van Dam came home around 2:30 a.m., then stayed up for an hour with her husband and friends. She said she made sure the children's bedroom doors were closed to keep from disturbing them, but didn't check on the children.

Danielle's disappearance was featured on the crime-fighting show "America's Most Wanted."