Police are investigating two men they say are "persons of interest" in the disappearance of an 8-year-old California girl.

Sandra Cantu was last seen 4 p.m. on March 27, when a surveillance video camera recorded her walking away from her family's mobile home in Tracy, Calif. Her mother reported her missing at about 8 p.m.

A Tracy police spokesman said officers searched the homes and towed the vehicles of the two men Monday.

Items collected in the searches were turned over to the FBI crime lab for analysis.

Police are not saying why the two men attracted the attention of investigators. Their names have not been released.

Sgt. Tony Sheneman told the San Francisco Chronicle the men are not related to each other and do not live together.

He wouldn't say how, if at all, the persons of interest are connected to the girl. Shenemen said the men were not named as suspects and were not arrested.

Meanwhile, the reward for information grew to $7,000. Investigators are tracking down the more than 150 tips that have poured in.

Police say there is no evidence that Sandra was abducted or the victim of foul play.

The missing girl is Hispanic, 4 feet tall, and weighs 45 pounds, with brown hair and brown eyes. She was wearing a pink Hello Kitty T-shirt and black leggings when she was last seen.

The Associated Press contributed to this report.

Click here to read more on this story from the San Francisco Chronicle.