The brother of ramen burger founder Keizo Shimamoto is contemplating legal action against L&L Drive-Inn, he has told the Honolulu Star-Advertiser.

The island-based quick-service restaurant with company-owned and franchised restaurants in Hawaii, across the mainland, and in other countries, announced plans to launch its own version, called a saimin burger, last week.

L&L also has emailed a newsletter containing a promotional poster for the burger to its franchisees, which will be called a ramen burger at mainland L&L locations, as well as a video of Jeff Shimamoto’s appearance on Hawaii News Now’s “Sunrise” program promoting his brother’s original product.

Jeff Shimamoto, who was in the islands to promote sales of his brother’s burger in January, is also an attorney who has contacted Hawaii attorneys to explore possible legal action claiming personal misappropriation of his likeness by L&L to promote its own product.

Keizo Shimamoto applied for a trademark for the ramen burger and his company-branded Go Ramen Burger on Aug. 2, 2013, and the latter was published for opposition by the U.S. Patent and Trade Office on Jan. 21.