Developments continue to come out in today's deadly shooting rampage at Fort Hood in Texas...Authorities there now say the suspected shooter is alive and in custody...Teri Okita has the latest.Sirens sounded at Ford Hood after a gunman opened fire...killing 11 people and injuring more than 30 others."Attention--take shelter immediately.'Soldiers brought some of their wounded comrades to waiting ambulances as SWAT teams moved in.Sources say the gunman responsible for the killings is Major Nidal Malik Hasan ... reportedly a psychiatrist and drug rehab specialist.Lt. Gen. Bob Cone says, "A single shooter was shot several times...however he was not killed as previously reported."The suspect opened fire at Ft. Hood's Readiness Center ... where soldiers who are about to be deployed ... or are returning from Iraq and Afghanistan ... undergo medical treatment.Hasan also gunned down people who were attending a graduation ceremony at a nearby theatre onLt. Gen. Cone says, 'SOLDIERS AND FAMILY MEMBERS AND CIVILIANS WHO WORK HERE ARE DEVASTATED.'Ft. Hood's commander is stunned and says the motive is still under investigation. As the violence unfolded, frightened family and friends waited for word about their loved ones."normally, he would call me to pick him up. But when I call back his phone just beeps and beeps."Ft. Hood ... the world's largest military installation and home to more than 50-thousand troops ... has been on lockdown.President Obama was briefed on the shooting rampage and the casualties ... many who are believed to be soldiers.President Obama: It is difficult enough to lose them in battles overseas ... Horrifying when they come under fire at a u-s base.The wounded have gone to several hospitals in the area.Many in the military community are wondering tonight how something like this could have happened.Teri Okita, CBS News.