The suspect jailed on 10 counts of murder in this week’s mass shooting in Colorado has been moved to another detention center because of “safety concerns and threats,” and he faces additional attempted-murder charges, officials said on Friday. Conway G. Gittens reports.The jailed 21-year-old suspect in Monday's mass shooting in Colorado that killed 10 people, including a police officer, had to be moved to another detention center because he faces "safety concerns and threats."A sheriff's spokeswoman told Reuters Ahmad Al Aliwi Alissa, who is being held without bail, was transferred Friday to another prison outside of Boulder County.Alissa who is facing 10 counts of murder and one count of attempted murder, will likely face additional attempted-murder charges, according to Boulder County District Attorney Michael Dougherty.Law enforcement across several agencies have been working around the clock still searching for a motive behind the shooting rampage, says Boulder Police Chief Maris Herold."Like the rest of the community, we, too, want to know why, why that King Soopers, why Boulder, why Monday? And unfortunately, at this time, we still don't have those answers."Officials say the semi-automatic weapon used in the attack was legally purchased six days before. Alissa purchased the Ruger AR-556 pistol, a weapon that resembles a semi-automatic rifle, after passing a background check.The owner of Eagles Nest Armory, where the firearm was purchased, said he was shocked by the shooting, telling Reuters: "Ensuring every sale that occurs at our shop is lawful has always been and will always remain the highest priority for our business."Officials revealed that Alissa also had another firearm in his possession at the time of the shooting that he did not use -- a 9mm handgun.Asked whether authorities suspected any link to international terrorism, the DA said investigators were looking into all aspects of Alissa’s background.Allisa made his first court appearance on Thursday, where his defense team asked the court for a full mental health examination.The Colorado shooting was the second mass shooting in the US in less than a week, once again stirring up the fierce debate over gun control.