more on this trend let's go to marianne lafferty life in our west coast bureau. >> high petty end.ortunately, both in the us are too familiar with these types of sudden violent attacks on innocent people there. in fact, this is the second tax just the last two weeks and unfortunately in last three months. couple of weeks ago a bombing in manchester arena targeted children attending and ariana grundy concert and that attack claimed lives of two people and injured more than 100 others as parents and young kids were leaving the arena. back in march another act of terror four people were killed and 50 injured in an attack on the westminster bridge when the suspect lead drove a car into strands and then stabbed and killed a nearby police officer. both of those attacks terror group isis claimed responsibility and in the wake of the manchester bombing britain terror threat level was raised to critical with thousands of troops deployed onto the street of britain. lastly, that that leveled was lowered back to severe. meanwhile, another sold-out concert plant in manchester on sunday, ariana