Schools and state offices hit by new threats

DENVER (Reuters) - Security alerts forced the evacuation of schools in Colorado and California, the Arizona State capitol and a NASA building in Houston on Friday and as U.S. authorities dealt with a rash of alarms in the wake of this week's massacre at Virginia Tech university.

Four days after the Virginia attack, and on the eighth anniversary of the shooting at Columbine High School near Denver in which 15 people died, a heightened sense of alert gripped the country, especially at educational institutions.

In Houston, NASA evacuated a building at the Johnson Space Center after a person with a gun was seen and a shot was fired, NASA spokeswoman Brandi Dean said. Police surrounded the building and it was not immediately known if anyone was hurt.

Johnson Space Center is home of Mission Control and the training center for NASA's astronaut corps.

A bomb exploded outside the Ponderosa High School in Parker, Colorado, not far from Columbine School, and officials caught a suspect who was carrying another explosive device.

"At this time it has not been determined what the device was," Douglas County Sheriff's Deputy Cocha Heyden said. There were no injuries reported.

Many schools and other institutions have received threats since Virginia Tech student Cho Seung-Hui shot and killed 32 people and himself on the university campus on Monday in the deadliest shooting rampage in modern U.S. history.

In Phoenix, Arizona police evacuated part of the state Capitol for several hours after a telephoned bomb threat, authorities said. State employees later returned to work after police swept the complex and declared it safe.

In Northern California, a man who threatened to go on a killing spree inspired by the Virginia Tech murders turned himself over to police on Thursday night.

Before Jeffery Thomas Carney turned himself in, schools in Yuba City and Marysville north of the capital, Sacramento, went into lockdown and said they would stay closed on Friday.

In Massachusetts, a part-time student was accused in a Boston court on Thursday of sending an e-mail threatening to kill an ex-girlfriend and recreate the Virginia Tech bloodshed at a local college.

In Santa Clara south of San Francisco, officials at Mission College evacuated about 2,000 students and several hundred staffers on Friday morning after finding an anonymous bomb threat in a bathroom, a spokeswoman for the college said.