By Don Ford

ANTIOCH (CBS SF) — A Bay Area veteran is desperately looking for a lost service dog.

His name is Leo and he’s a Golden Retriever-Chow mix. He was last seen on Lower Sherman Island in Antioch on the Fourth of July.

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Jess Walker is looking for Leo. He belongs to Walker’s friend, U.S. Army veteran Nick Bilbao.

Leo helps Nick deal with post-traumatic stress syndrome.

Nick was out of town for the weekend, and Walker was dog-sitting Leo. Leo became separated from him while celebrating the Fourth of July on the island in the delta.

Walker said, “He was playing around a little bit in the water and lying in the sun and then, I guess some fireworks were set off, from what I know and he took off.”

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A group searched all weekend but Leo is still missing. He is invaluable to Nick. He is a member of the family and a vital help with her condition. Contra Costa Animal Services is on alert and hoping to reunite this veteran with her service dog.

Contra Costa Animal Services spokesperson Steve Burdo said, “Our officers took a walk through the kennel, look to see if we could identify the animal. We did not.”

Leo has a microchip implanted under his skin and if he is found, like all dogs, he will be scanned and a coded number will identify him at once.

Meanwhile, Walker is helping her friend Nick by searching the shelters for Leo.

Animal shelter folks say by now the dogs fur could be matted, have dried mud, and could appear to be very different than the photographs we’ve seen. So, they are asking if anyone sees a dog that remotely resembles Leo, please give local authorities a call.

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A Craigslist posting says Leo has saved his owner’s life multiple times and now “it’s our turn.”