Honolulu police say they were investigating a report of suspicious circumstances at or in the Campbell Building at 1001 Kamokilo Boulevard in Kapolei Tuesday afternoon.
At around 2 p.m., police got a phone call saying someone allegedly had a gun in a holster.
Officers secured the Campbell Building as a precaution and searched all of the floors to look for the person.
The all clear was called at around 3 p.m.
Witnesses at the scene say the building was on lockdown as police investigated.
U.S. Post Office spokesman Duke Gonzales says employees at the Kapolei Post Office were told by police to leave immediately, but were not told why.
Witnesses also say people were standing outside of the Kapolei Library on Manawai Street.
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