Sibling fugitives had underground bunker: Cops

A massive FBI search is under way for three siblings wanted in connection with a crime spree spanning at least two states. Police believe the group opened fire on a police car in Florida before robbing a bank in Georgia.

On Monday, the search for 29-year-old Lee Grace Dougherty and her two younger brothers, Dylan, 26, and Ryan, 21, continued to heat up as police released a dashcam video showing their initial flight from justice.

Fugitive siblings' mother: Give up

A police officer in Zephyrhills, Fla., was attempting to stop a white four-door sedan for speeding when he was led on a high-speed chase. CBS News Correspondent Elaine Quijano reported investigators say the Doughertys opened fire on a residential street, and then, in a drugstore parking lot. The officer was uninjured, but the three siblings escaped after shooting out his tire.

Pasco County, Fla. Sheriff Chris Nocco said, "We do know there were points where they slowed down in an attempt to kill this police officer."

Just hours after the high-speed chase, police say, the group robbed a bank in Valdosta, Ga. Witnesses say they fired shots into the air and ordered everyone to the floor before leaving with an undisclosed amount of money.

Jim Sloop, a witness, told CBS News, "It was bold to come out and do such a thing in broad daylight."

The three are now wanted for attempted murder and armed robbery.

Their mother, Barbara Bell, of East Palatka, Fla., told police she received a text message from Ryan Dougherty on the day of the robbery saying, "At some point, we all have to die." Later, she made a public appeal for her children to surrender, saying, "Please prove me right and everybody wrong by doing the right thing now, and turning yourselves in."

Police believe the group is armed and extremely dangerous and may have been planning their crime spree. A search of the home where the suspects reportedly lived revealed a sophisticated underground bunker system, authorities say.

At this point, the three Doughertys' whereabouts are unknown and police are reportedly following tips from as far away as Tennessee.

On "The Early Show," Sheriff Nocco, speaking from Tampa, Fla., warned the siblings are dangerous.

"We don't want people to think that these are just three kids," he said. "These are three felony (offenders). They've actually committed numerous felonies throughout their lives. They're street-smart. They know what they're doing, and we need the public's assistance to help capture them."

Nocco says he hopes their recklessness will lead to a mistake on their part.

"Everybody's bound to do that," he said. "But as we want the public to realize, these are three, very dangerous people."

Nocco added, "Ryan has 14 felony arrests. His sister had at least five. She's wanted also for hit-and-run battery. Dylan has drug charges. But they've actually have a large arsenal, too, besides that bunker that we discovered, you know, these people out there, they're extremely dangerous. ... And the biggest thing that we're afraid of right now is they have three options. One is that we hope they turn themselves in. That is what we hope ends this. The second thing is right now, you know, they did the bank robbery. So they got a little bit of money. But we know they're going to need some more money to survive. Right now, we think they may go out there and commit another felony. The third thing is that they may end this in a battle with law enforcement. But we have a lot of resources, and I promise you, we will win that battle."

The Doughertys, Nocco said, aren't likely to surrender quietly.

He said, "Unfortunately, they're suspects in (attempted) killing a law enforcement officer in Florida. They committed bank robbery where they have high-caliber rifles. They're not afraid to use them. I don't think they're afraid of a battle. But what we keep trying to push is (that) we want them to turn themselves in peacefully."

Wragge asked about the impact of the national media exposure on the group.

Nocco said the siblings' options "keep narrowing in."

"Their mother knows best," he said. "She asked for them to turn themselves in, and we hope that her appeal leads them to come in peacefully. Because they should realize their future isn't that bright right now, while they're on the run. And they'll have better options if they turn themselves in."

Nocco shared a wanted poster on "The Early Show." It said, "Armed and Dangerous. Suspects driving a white Subaru Impreza, New York tag, #FBE5900. If seen, do not approach, call 911."