Read our Privacy noticeFederal authorities were investigating a bomb threat at Huntington Hospital in Pasadena on Saturday after an evacuation was prompted by a caller who allegedly identified himself as a member of the extremist online group 764. As a precaution, incoming emergency traffic was diverted to nearby hospitals after the bomb threat was reported. The FBI has described 764 as "a violent online group made-up of individuals who seek to coerce and manipulate children into engaging in unspeakable acts against themselves, animals, and other children, even suicide." Officials added that the group is also known to engage in "swatting" -- placing false emergency calls to trigger armed police raids. In April, a bomb threat at Southern California Hospital in the Culver City area prompted a response from explosives-detection K-9 units and was ultimately determined to be a swatting incident.