SAN DIEGO (AP) — A man accused of piloting a boat overloaded with migrants that crashed into rocks off San Diego's coast and killed three people kneed a U.S. Border Patrol agent in the face who was trying to put a leg shackle on him on the beach, authorities said.

Investigators said in an affidavit filed Tuesday in federal court in San Diego that the agent was not seriously injured but the hit left a red mark on his forehead.

A total of 33 people were pulled from the water after the 40-foot (12-meter) trawling-style boat smashed into rocks and broke apart Sunday, tossing people into the rough sea off Cabrillo National Monument. Besides the three who died, two others were still hospitalized, including one in critical condition.

Investigators say Antonio Hurtado, a U.S. citizen, was piloting the boat, and he was arrested on suspicion of bringing in or harboring undocumented immigrants and assaulting an officer, according to the affidavit. Twenty-one passengers identified Hurtado in a photo lineup as the captain of the vessel.

He was treated in a hospital and turned over to immigration authorities. His lawyer, Melissa Bobrow, declined to comment.

The migrants told investigators they paid between $15,000 and $18,000 each to be smuggled into the U.S. on the boat.

All but one were Mexican citizens, including two 15-year-olds who were traveling alone, a boy and a girl. A Guatemalan man remains hospitalized.

Maria Eugenia Chavez Segovia, 41; Maricela Hernandez Sanchez, 35; and Victor Perez Degollado, 29, drowned after suffering blunt-force injuries to their heads, according the San Diego County medical examiner's office.

Navy rescue swimmer Cale Foy did his best to save them. He was hiking with his wife and three kids when he noticed the vessel approaching the rocky, wind-swept San Diego coastline as 5- to 8-foot (1.5- to 2-meter) waves were crashing.

A moment later, a wave slammed the boat, and Foy saw it hit the rocks. He spotted people tossed into the rough sea before the vessel broke into pieces.

“All of a sudden, we see people jumping into the waves and on top of the rocks, and it was: ‘I have to be there. I have to help,'" Foy said.

He immediately ran toward the shore in what would become the most dramatic rescue mission of his 17-year career. Foy and another young sailor who was also out hiking and is in basic training as a Navy SEAL recruit were among the first to respond.

“We could hear people frantic, kind of chaos, screaming,” Foy said.

In a T-shirt, pants and hiking boots, Foy ran into the waves, took a chance and dove under, praying that he would not be slammed into rocks below.

After Foy and the Navy SEAL recruit got past the pounding surf, they came upon a large piece of the boat's cabin and grabbed it to rest.

Then the two headed toward the screams. They helped three men who survived get to the wreckage.

Then Foy saw a woman face down in the water, wearing a life preserver. She was unconscious.

Foy used his body to keep her head out of the water, carrying her on his chest as he swam toward the floating debris. He placed her on it and then pulled it toward a lifeguard boat that had arrived.

He got her into the boat, hopped in and started CPR on her as they rolled over the waves.

Foy traveled with the lifeguard boat back to land and continued to do CPR for 20 more minutes.

Despite his efforts, she died, he said.

Foy stayed for another two hours on the dock, helping tend to people brought in on the lifeguard boats.

In the end, Foy and the Navy SEAL recruit got six migrants to the floating wreckage. Four of them survived.

“We just jumped in and helped out with what we could," Foy said.