OAKLAND — Authorities allege a Pleasanton man urinated on a stack of Walmart purchases from his parents’ recent shopping trip, then used two 3D-printed handguns later that night to gun down his father in their shared home, according to court records filed Wednesday.

Alameda County prosecutors have charged Lucas Chan, 28, with murder in the fatal shooting of his father, Lance Chan, who later died at a hospital. The younger Chan also faces six additional counts tied to several suspected homemade bombs that investigators seized from his bedroom, among other charges, according to court documents.

The shooting brought a gruesome end to what authorities described in court papers as an otherwise ordinary day, which began with Chan’s parents going shopping at Walmart with another couple.

Lucas

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