LOS ANGELES (CBSLA.com) — A suspicious package was found on Thursday underneath the main headquarters of the Los Angeles Police Department.

An envelope containing an unidentified white powder was discovered in an underground area of the building at 100 W. First Street sometime around 11:30 a.m., police said.

KNX 1070′s Pete Demetriou reports a threatening letter was also found.

“Records & Identification division down on P-1 level opened an envelope that contained white powder with a note that basically said, “You all deserve to die’,” said LAPD Deputy Chief For Counterterrorism Mike Downing.

Front lobby access as well as access to the underground area was restricted after police found the package, but the building was not evacuated.

A hazardous materials squad examined the item and began allowing people back inside the restricted areas at around 1:00 p.m.