The search is underway for a hacker who caused panic in Dallas after 156 emergency sirens were heard going off over the weekend. It began at 11:42 p.m. Friday as the sirens, which warn about approaching tornadoes, went off. However, there was no inclement weather or tornados headed to the area. Some even feared it might be a terrorist attack coming on the heels of the U.S. missile launch against Syria. The sirens were shut off and then turned back on more than a dozen times during the night.