Fugitive Siblings 'Committed to One Another' on Dangerous Mission: Investigators

Aug. 8, 2011 — -- Text messages and tweets by three fugitive siblings who shot at a police officer and robbed a bank reveal a dangerous mindset and a firm bond between the siblings, investigators said today.

"We've certainly seen their mindset when... They shot at a law enforcement officer outside of Tampa Bay, Fla., and when they fired inside that bank in Valdosta, Ga. But these additional texts and tweets have given us additional insight," FBI Special Agent Stephen Emmett told "Good Morning America" today. " We are concerned and feel that they are going to continue and cause problems to say the least for law enforcement."

Ryan Dougherty, 21; his sister Lee Grace E. Dougherty, 29; and half-brother Dylan Dougherty Stanley, 26, have been on the lam since Aug. 2 when they shot at a police officer attempting to pull their white Subaru Impreza over for speeding. A few hours later, they robbed a bank in Georgia.

While on the run, they've sent a text message to their mother that read, "There's a time for all of us to die." Investigators said that previous tweets also reveal details about the siblings' bond. Investigators won't discuss the content of those tweets.

The three siblings, dubbed the Dougherty Gang, were allegedly driving as fast as 100 miles per hour on Aug. 2 when a Zephyrhills, Fla., police officer attempted to pull them over. They fired 20 shots at the officer and escaped when one of the bullets hit the police car's tire. The officer was not injured.

Doughtery Gang Is Heavily Armed and Devoted to Each Other

A few hours later that same day, about 200 miles North in Valdosta, Ga., the Dougherty gang allegedly robbed a bank while wearing masks and firing rounds from an AK-47 at the ceiling. They escaped with an undisclosed amount of money, police said.

"It's very unusual to have siblings like this so well armed, so committed to whatever mission that they think they're on and to have demonstrated such propensity for violence," Emmett said. "The problem that we feel we're facing is that they're committed to each other as siblings, so that's going to create additional issues for any law enforcement that is confronting them."

Police have found an elaborate bunker, constructed out of two 40-foot storage containers, under an abandoned house where the trio reportedly once lived.

The siblings share a lengthy criminal history that includes 20 felonies among them. The charges range from drug possession to battery and to burglary. Ryan Dougherty's latest crime may have sent him and his siblings on their current spree.

Ryan Dougherty had recently been put on court probation and was forced to register as a sex offender after sending explicit text messages to an 11-year-old girl. He feared that his conviction would keep him from seeing his baby on the way.

Barbara Bell, the mother of the fugitive siblings, has publicly appealed to her children to turn themselves into authorities.

"Only mom knows what good people you are inside," Bell told ABC Affiliate WFTS. "Please prove me right and everybody wrong by doing the right thing now and turning yourselves in."

"Your lives are not over. You've made some bad mistakes, but so far no one has been physically harmed," Bell said. "The only safe thing, the only right thing, the only good thing to do is to turn yourselves in."

The fiance of Lee Grace Dougherty told a local paper, "It's hard for me to see this thing turning out happily."

Authorities fear the same thing.

"They are well armed. They have at least an AK-47 assault rifle and a MAC -10 or MAC -11 type machine pistol. These are high capacity, high rate of fire weapons that are normally seen by the military or law enforcement. These weapons are very damaging weapons and they've shown that they will fire them," Emmett said.

Authorities have launched a digital billboard campaign throughout the southeast.

Anyone who sees them or their is asked to call the FBI at (404) 679-9000 or the Valdosta Police Department at 229-293-3145. If you wish to remain anonymous you can call 229-293-3091.