In this undated FBI photo, Ryan Edward Dougherty, left, Lee Grace Dougherty and Dylan Dougherty Stanley are shown. Investigators say they received a tip that three Florida siblings accused of firing shots at a Florida police car and then robbing a bank in south Georgia may have traveled to Tennessee. Authorities have been pursuing the siblings since Tuesday, Aug. 2, 2011. (AP Photo/FBI via the Atlanta Journal & Constitution)

NEW PORT RICHEY, Fla. - Pasco County Sheriff Chris Nocco says he hopes three fugitive siblings will make a mistake as they continue to elude authorities after allegedly shooting at a police officer in Florida and robbing a bank in Georgia.

Appearing on CBS's "The Early Show" Tuesday, Nocco called the Zephyrhills siblings "extremely dangerous." He says they wouldn't be afraid to "get into a battle with law enforcement."

A nationwide manhunt began Aug. 2 when the trio took off after firing shots at a Zephyrhills police officer who tried to pull them over for speeding. Hours later, three people wearing masks robbed the Certus Bank in Valdosta, Ga., about 210 miles north.

Authorities say a white sedan similar to the one involved in the Florida shooting has been spotted in Georgia and Chattanooga, Tenn.