Last month, Americans' sense of security was shattered when a gunman opened fire at a Jewish Community Center in Los Angeles. This crime and similar acts have increased awareness of a growing trend: The number of hate groups is increasing, according ... (more)to experts. "Last year the number of hate groups went up 20 percent," says Mark Potok, a spokesman for the Southern Poverty Law Center, which tracks such groups. "It was a dramatic rise." CBS News 48 Hours explores this phenomenon, focusing on the recent shooting in Los Angeles and a Pennsylvania family forced to flee from racists intent on terrorizing them. Survivors' Stories: Victims and their parents speak out for the first time in the aftermath of the shootings at the North Valley Jewish Community Center in Los Angeles. 48 Hours Correspondent Susan Spencer reports. Hate Hits Home: Bonnie Jouhari, a fair housing advocate in Reading, Penn., is threatened by a hate group for her efforts to integrate housing and fight racial harassment. This campaign of intimidation forces Jouhari and her daughter Dani to relocate. Jouhari's enemies find out where she moved and continue their campaign. Find out Jouhari's response to these threats in an exclusive CBS.com interview.