UPDATED 10/03/11 7:30 a.m.

CHICAGO (CBS) — Police resumed their search Monday morning for a man who went missing in Lake Michigan over the weekend.

As CBS 2’s Susanna Song reports, at this point, officials believe it is unlikely that James Garcia, 51, of Berkeley, survived.

Garcia disappeared in the choppy waters of Lake Michigan Saturday night, after relatives say he went for a swim near the Oak Street Beach.

Divers and search boats resumed their search at sunrise. They have been working in what was being classified as a “recovery” — not a rescue — mission.

“He’s going to be missed,” Garcia’s son, James Garcia Jr., told CBS 2’s Kristyn Hartman. “It’s just hard, hard. It’s hard to say what I feel right now. The feeling is hurt.”

Helicopters, boaters and divers searched Lake Michigan throughout the day Sunday to find Garcia.

Meanwhile, family members on Sunday were trying to piece together what happened. But at some point Garcia ended up at the lakefront following a birthday celebration.

“I just know they were out having a good time. I guess he decided he wanted to go for a swim, and I guess the currents took him under,” Garcia’s son, James Garcia Jr., told CBS 2’s Kristyn Hartman.

Garcia Jr. said five friends who were with Garcia tried to grab his father and pull him out, but the current “just wiped him.”

“He was a frequent goer of the beach, and he loved going out, and he just went to clear his mind,” Garcia Jr. said. “He loved the great outdoors. Just to be outside was good.”

Garcia’s family gathered outside a Franklin Park home bedecked in Halloween decorations, to support each other and remember a great father and grandfather.

“He’s a loving uncle. He’s like a father to me,” said Garcia’s niece, Andria Garcia.

Family members say Garcia’s 4-year-old granddaughter keeps asking why everyone is crying. They haven’t had the heart to tell her that her grandpa is missing.

“He gives his shirt off his back. He’d give his last dollar to anybody. He’s just a great man,” Garcia Jr. said.

It is heartbreaking, the family says, knowing the outcome is grim.

“We just want him found, that’s it,” Andria Garcia said. “I love you, tio. I’m going to miss you a lot.”

Upon returning Monday, divers and boats with special sonar equipment resumed their search.