OS ANGELES, Feb. 22 — A neighbor of a 7-year-old San Diego girl who disappeared three weeks ago was charged today with kidnapping her after DNA tests showed that the child's blood was on an article of his clothing and in his motor home, the police said.
A police spokesman, David J. Cohen, said the authorities were hopeful that the girl, Danielle van Dam, was still alive. But Mr. Cohen added that "the more time that goes by, the less likely it is that may come true."
The neighbor, David Westerfield, 49, was arrested about 10:45 a.m. as he left his lawyer's office in downtown San Diego, the police said.
Mr. Westerfied, who lives just a few doors away from the van Dam home, came under police scrutiny almost immediately after the girl was reported missing on Feb. 2. He was jailed today and was expected to be arraigned on Tuesday.
The authorities have searched his home several times, impounded his sport utility vehicle and mobile home and questioned him at length, asking him at one point to retrace his activities in the desert the weekend of Danielle's disappearance. Child pornography was found in the home, the police said today.
"We think we've got the person," Mr. Cohen said, "but we still don't have Danielle, and we'll continue to analyze evidence."
The search for Danielle will continue over the weekend, and organizers were appealing for more volunteers.
"We are very happy that police have made an arrest," said Brenda van Dam, the girl's mother. "But the fact still remains that we don't have our daughter. We still need to find Danielle."
Danielle was last seen about 10:30 p.m., Friday, Feb. 1, when her father put her to bed. She was discovered missing from her room about 9 a.m. the next day.
The van Dams have described Mr. Westerfield, a self-employed engineer, as "an acquaintance," but not a friend.
"We've seen him since we moved in," Mr. Van Dam has said. "We wave to him. We say hello to him when we drive by."
Mr. Westerfield has told reporters that he saw Brenda van Dam at a bar near their home the night before the girl was discovered missing. The police have said that Mrs. van Dam was at the bar with friends and that she returned home about 2:30 a.m. with the friends and had pizza.
Despite the arrest, the police are providing no details about the motive for the kidnapping or how it might have occurred.
Steven E. Feldman, one of two lawyers representing Mr. Westerfield, declined to discuss the case. But he issued a statement saying, "Mr. Westerfield has merely been arrested today, but under our system of constitutional law he is presumed innocent."