(FOX 11) - A wave of emailed bomb threats Thursday to dozens of schools, universities and other locations in Southern California and across the U.S. put law enforcement agencies on alert, but were not considered to be credible.
The Los Angeles County Sheriff's Department said the agency is aware of the threats and conducting investigations, but "no threat has been substantiated.''
#LASD is one of several Police Departments nationwide to receive threats to several businesses within our vast jurisdiction. We treat these each with the gravity they deserve & are conducting investigations, but no threat has been substantiated. Please call if you have info. pic.twitter.com/b4kDaTGhOW— LA County Sheriff's (@LASDHQ) December 13, 2018
Similar threats were also reported in New York City, San Francisco and other areas across the country. The emailed threats demand cash in Bitcoin to be paid by the end of the day or an explosive device will be detonated.
Garden Grove police in Orange County said the agency received several calls around 11:15 a.m. from local businesses reporting a bomb threat by email.
"The threat demanded cash in Bitcoin or they would blow up the business. Similar threats were reported in cities across O.C. These threats are unfounded,'' the Garden Grove Police Department posted on Twitter.
The Riverside County Sheriff's Department said it was one of several local agencies experiencing an influx of email threats and was investigating each threat.
"At this time no threat has been substantiated," the department said.
RSO is one of several S. Ca. LE agencies experiencing an influx of email threats. RSO takes these threats very seriously and is conducting an investigation into each threat. At this time no threat has been substantiated. We will provide an update when addtl. info is available— Riverside County Sheriff's Dept (@RSO) December 13, 2018
The New York City Police Department said the threats were meant to cause disruption and compel recipients into sending money and are not considered credible.
Some of the emails had the subject line: "Think Twice."
Across the country, some schools were closed early and others were evacuated because of the threats.
Penn State University noticed students via a campus alert. Near Atlanta, people were ushered out of a courthouse.
The Associated Press contributed to this report.