The box contains handwritten notes, stickers and bracelets that loved ones placed at a tree on Garretson Road, remembering Brian Conklin.
Conklin died last May when his vehicle veered off Garretson Road at the intersection of Hill Lane, struck a tree and went up in flames.
"The box itself was a gift from friends to protect it all, and now someone has taken this from us -- ALL of us," Christine McGinn Conklin wrote on Facebook.
Anyone with any information is asked to contact the Bridgewater Police at 908-722-4111.
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