The 91 Freeway was closed in Corona Sunday night after someone reported hearing gunshots.
Westbound lanes were open as of 10:40 p.m., and eastbound lanes reopened around 11 p.m.
A large police presence could be seen in the area from NewsChopper4.
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The Corona Police Department concluded their search for injured people and evidence around 2:30 a.m. Monday.
No one was arrested, but the investigation was ongoing, police said.