Republican National Committee headquarters under lockdown after being sent vials of blood

The Republican National Committee headquarters in Washington, D.C., was under lockdown Wednesday morning after someone sent vials of blood to the building, three sources familiar with the situation told NBC News.

Capitol Police responded to the scene at 7:45 a.m. after a report of a suspicious package, police said.

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The package contained two vials of blood and was cleared by the Hazardous Incident Response Division, the police told NBC News. The source of the package and its contents are under investigation.

It is unclear if a suspect is in custody.

The road to the RNC headquarters has been reopened to traffic, and Capitol Police have left the scene.

This story first appeared on NBCNews.com. More from NBC News:

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