Drean Rucker, a high school All-American linebacker who was among USC's top football recruits, was presumed drowned after a swimming accident off Huntington State Beach late Monday, authorities said.
Members of Rucker's family kept vigil at the beach late Tuesday while lifeguards continued to search for the 18-year-old from Riverside.
Rucker was at a cookout when he and a friend entered the water shortly after 8 p.m. Monday, said Mike Brousard, lifeguard supervisor. There were no lifeguards on duty at the time.
A short time later, the friend returned to shore seeking help for Rucker, who he said was having trouble in strong riptides. Rescue units, including a Coast Guard helicopter, looked for Rucker until about 9:30 p.m., when the search was called off until Tuesday.
Although Rucker's family was holding out hope that Rucker would be found alive, authorities said that was highly unlikely.
"He's listed as missing, but we're assuming the worst at this point," Brousard said. "Somebody saw him slip under the waves. I don't think we're going to have a happy conclusion to this."
Brousard said he could not confirm reports that Rucker could not swim.
USC Coach Pete Carroll expressed sympathy for Rucker's family.
"The hearts and prayers of the Trojan family go out to Drean's family at this difficult time," said Carroll, who withheld further comment because of the ongoing search.
Rucker was part of a USC recruiting class that many considered the school's best since the 1970s, when the Trojans won three national championships.
News of Rucker's accident was greeted with shock and sadness at Moreno Valley Canyon Springs High. He graduated this past spring.
"A lot of kids at summer school are taking it pretty hard," said Jeff Stovall, boys' basketball coach. "I just saw him the other day. It's very sad."
Stovall said Rucker was among the most popular students at Canyon Springs.
"Everybody on campus liked him," he said. "He was a real good kid, very quiet."
Rucker, 6 feet 2 and 235 pounds, was widely considered the No. 1 high school linebacker in Southern California last season. He had 153 tackles, including 20 for losses, and two interceptions to help Canyon Springs reach the Southern Section Division V semifinals.
Greg Biggins, a recruiting expert for Student Sports Inc., said Rucker was talented enough to possibly play as a freshman for USC.
"He had great size -- he looked like a college linebacker now," Biggins said. "He was fast, instinctual. He made a ton of plays. He was still a little bit raw, but ability-wise he was as good as I've ever seen.
"He was a phenomenal kid. I always enjoyed talking to him."
Rucker was selected an All-American by Super Prep magazine and was named to the all-state team by Cal-Hi Sports and to The Times' All-Star team. He played for the California team in the CaliFlorida Bowl on Jan. 4 at Mt. San Antonio College in Walnut.
Rucker's father, Andre, made an emotional plea to the media to respect his family's privacy and let them hold out hope for his son's survival.
This was the third time in a week that a swimmer had apparently drowned off the Orange County coast. Lifeguards made 1,038 rescues at Huntington Beach in the first two weeks of July, Brousard said.
"Conditions have been exceptionally dangerous for the last month," Brousard said. "We've had strong riptides.... If you don't swim well, it can have fatal consequences."
Staff writer Zeke Minaya contributed to this report.