People hold the names of some of the 17 people killed during a shooting at Marjory Stoneman Douglas High School on February 16, 2018 in Boca Raton, Florida. Police arrested 19 year old former student Nikolas Cruz who has confessed to the shooting. Pic/Getty Images/AFP

Nikolas Cruz, the 19-year-old youth who killed 15 students and two staff members with an AR-15 automatic rifle in Florida, told police that voices in his head told him how to carry out the attack, police said on Friday. Cruz was arrested and charged on Thursday on 17 counts of premeditated murder, after confessing to the mass shooting of students at Marjory Stoneman Douglas High School in Parkland on February 14, Valentine's Day, Efe reported.