Authorities searched a home in the US state of Colorado early today, seeking any link between two deadly shooting sprees at Christian religious centres that left both communities baffled and stunned.

The families of Columbine school shooting victims pledged to appeal against a judge’s decision to seal information about the two killers that they say might have helped prevent the Virginia Tech massacre.

Allegations of voter intimidation and problems with electronic voting machines hampered the crucial US midterm elections today as Americans went to the polls in the battle for control of Congress.