Police expanded their search for two missing boys to a 100-square-block area and announced a $17,000 reward as they began a fifth day with no substantial leads into the youngsters' disappearance.

"We absolutely don't have any information about where they would be and why they would leave of their own accord," police spokeswoman Anne E. Schwartz said at a news conference late Thursday morning. "We just simply don't know where they are."

Purvis Virginia Parker, 11, and his 12-year-old pal Quadrevion Henning aren't the type to have wandered away, their families said. Purvis is a quiet boy who dreams of becoming an artist, and Quadrevion has a stack of honors from his school for good behavior and attendance.

"He wouldn't know anywhere to go. He didn't know anyone outside his rim," said Quadrevion's grandfather, Garry Henning. "That door never opened unless I knew where he was going."

Purvis' mother, Angela Virginia, said they she believed they were taken against their will.

The boys were out playing Sunday afternoon when he last saw them. When they didn't return home that evening, their families called police.

Dozens of officers spread out across the northwest Milwaukee neighborhood in an escalating search, knocking on doors and searching vacant buildings, wooded areas and even the sewers and nearby ponds for any sign of the youngsters.

Fliers with the Purvis and Quadrevion's pictures cover windows and cars in the boys' neighborhood, and the National Center for Missing and Exploited Children has posted their photos online.

Schwartz said hundreds of calls had come in to a tip line, but none provided substantial leads.

The reward fund was started Wednesday was $5,000 from a local company, Dawes Rigging and Crane Rental, and grew to $17,000 for information leading to the boys' safe return.

Someone must have seen something, said Latrice Kazee, 33, Purvis' godmother.

"They're not talking, and I don't know why 'cause this is no game," she said.