Bomb threats sent to locales throughout the nation appear to be hoax, law enforcement says

WASHINGTON (FOX 5 DC) - Police departments in cities throughout the U.S. are investigating a number of bomb threats reportedly sent to businesses via email.

"We are aware of the recent bomb threats made in cities around the country, and we remain in touch with our law enforcement partners to provide assistance," the FBI Washington Field Office posted on Twitter. "As always, we encourage the public to remain vigilant and to promptly report suspicious activities which could represent a threat to public safety."

Law enforcement agencies across the country dismissed the threats, which they said 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." The sender claimed to have had an associate plant a small bomb in the recipient's building and that the only way to stop him from setting it off was by making an online payment of $20,000 in Bitcoin.

Other law enforcement agencies also dismissed the threats, which were written in a choppy style reminiscent of the Nigerian prince email scam.

FOX 5's Lauren DeMarco says several locations in Washington D.C. have received emailed threats and even led to the evacuation of an office building in the 5100 block of Wisconsin Avenue in Northwest D.C.

D.C. police say they are investigating these threats, but they are not deemed credible and no one has complied with their demands.

Montgomery County police say they are aware of bomb threats that have been received across the county.

Frederick police in Maryland indicated that they've received reports from different locations since approximately 2 p.m. Each incident has been cleared, they say.

In Loudoun County, the sheriff's office says "no credible threats have been found."

The New York Police Department says officers are monitoring multiple threats sent to businesses through the city, as are police in the Boston area, and elsewhere.

Police in Michigan told FOX 2 that they are investigating bomb threats in Detroit and Ann Arbor.

Across the country, some schools closed early and others were evacuated or placed on lockdown because of the hoax. Authorities said a threat emailed to a school in Troy, Missouri, about 55 miles (88 kilometers) northeast of St. Louis, was sent from Russia.

The bomb threats also prompted evacuations at city hall in Aurora, Illinois, the offices of the News & Observer in Raleigh, North Carolina, a suburban Atlanta courthouse and businesses in Detroit.

"Organizations nationwide, both public and private, have reported receiving emailed bomb threats today," Michigan State Police spokeswoman Shannon Banner said. "They are not targeted toward any one specific sector."

Penn State University notified students via a text alert about threats to a half-dozen buildings and an airport on its main campus in State College, Pennsylvania. In an update, the school said the threat appeared to be part of a "national hoax."

Officials at Columbine High School in Colorado were dealing Thursday with a bomb threat of a different sort. Students were being kept inside for the rest of the school day after someone called in a bomb threat against the school.

The Jefferson County, Colorado, Sheriff's Office said the caller claimed to have placed explosive devices in the school and to be hiding outside with a gun.

There is nothing to validate the threat was found at Columbine, where 12 students and a teacher were killed by two students in 1999, according to Sheriff's spokesman Mike Taplin.

Two dozen other Colorado schools were also temporarily placed on lockout, meaning their doors were locked but classes continued normally, as the threat was investigated.

The Associated Press contributed to this report.