A 4-year-old Southern California boy visiting the beach for the first time had his prosthetic leg stolen but hundreds of people have reached out to help him replace the limb.

Liam Brenes of Rancho Santa Margarita and his parents went to Crystal Cove State Park in Orange County on Sunday. The family left the custom leg, which had a "Star Wars" decoration, and other items on the beach while Liam, wearing an older leg, explored the tide pools.

"We were in the water for two hours and came back and everything was gone," Liam told KABC-TV (http://abc7.ws/2a5TB0l). "They stole my leg."

Also taken were his clothes and shoes, a camera and other items, including a pair of eyeglasses belonging to one of his brothers, Aiden Brenes.

Liam was born without a fibula, or calf bone, in his right leg. It was amputated below the knee when he was about 1 year old. It hasn't slowed him down, though. Liam takes karate lessons and plays soccer.

After the theft of his leg became known, offers of help poured in.

A family friend started a GoFundMe account that as of Tuesday had raised more than $15,000 dollars to pay for a new leg.

"Both parents will have to take multiple days out of work as well as traveling to and from Los Angeles for the doctor visits, fittings, molding, etc. This is going to be a very hefty expense to replace such an important and desperately needed prosthetic," said the funding page established by Ann-Marie Brasil.

It was unclear whether insurance would cover the expense, the page said.

Any donations that are left over will pay for future expenses for Liam, such as sending him to a mountain camp for child amputees, and for future surgeries that the boy might need, the page said.

In addition, several prosthetics crafting firms have offered to help, and Robert Herjavec of ABC's "Shark Tank" also offered to buy a replacement, which can run $10,000 or more.

"It's amazing that one act of selfishness has brought out so much selflessness," Liam's mother, Amanda McFarland, told the Orange County Register (http://bit.ly/2a5fEVh) on Tuesday. "The amount of good because of that action is tenfold. It's definitely restored my faith."