Monday's one-alarm fire burned outside 834 Delna Manor Lane, a residential street near South Bascom Avenue and Downing Avenue, fire Capt. Mary Gutierrez said.
At least eight similar fires have burned in the neighborhood since Sept. 26, and investigators believe they may be related, Gutierrez said.
"The majority seem to be happening after dark," Gutierrez said.
She said the fires have burned in back or side alleys of large, multi-tenant residential buildings, some near Dumpsters, brush or trees.
So far, Gutierrez said, none of the fires have spread to the buildings, but fire investigators are still concerned.
"We are taking this seriously because there is a high potential for property loss and loss of life," Gutierrez said.
No suspects have been identified yet, she said.
Anyone with information about the fires is asked to call the San Jose Fire Department's arson tip hotline at (408) 272-7766.