Police on the scene of a lockdown at Mission College in Santa Clara on May 6, 2013. Investigators said the lockdown was prompted after a cardboard cutout of a gun was mistaken for a real one. (CBS)Police on the scene of a lockdown at Mission College in Santa Clara on May 6, 2013. Investigators said the lockdown was prompted after a cardboard cutout of a gun was mistaken for a real one. (CBS)