LOS ALTOS (CBS SF) – Authorities responded to a Los Altos home Monday after a grenade more than 100 years old, dating back to World War I, was discovered.

Around 10:15 a.m., Los Altos Police said they received a call from resident on the 1700 block of Christina Drive after the grenade was found in the bedroom of an elderly relative.

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When officers arrived, four adjacent homes were evacuated. Other nearby residents were told to shelter-in-place, police said.

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Additional resources, including the Santa Clara County Sheriff’s Office bomb squad, along with paramedics and PG&E, responded to the scene. The sheriff’s office determined that the device was a vintage grenade that was potentially live.

Police said the bomb squad decided to detonate the device in the backyard of the home. After mitigating fire hazards in the area and PG&E conducting an underground service assessment, the grenade was detonated without incident.

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No injuries were reported.