A nervous Decatur mother was awaiting word Monday on her 26-year-old daughter who went missing on a boat in Miami the night before.

Rebecca Lamar was filled with anxious questions Monday afternoon. She had yet to hear from any authorities. She had only received a call from a relative, who alerted her of the situation.

“You would think you would get a call,” she told the Atlanta Journal-Constitution. “It’s not making any sense.”

Her daughter, Lauren Jenee Lamar, who grew up in metro Atlanta, was the subject a multi-agency search in the waters off Miami, where she had moved a few years ago. About a dozen boats and a helicopter had been looking for her for about 13 hours, to no avail, authorities said.

Authorities had yet to determine the precise circumstances surrounding her disappearance.

Lauren Lamar had been out on a 30-foot boat with two other people. When the boat returned to shore and docked at Matheson Hammocks Marina at about 11 p.m. Sunday, the other passengers realized that she was missing, said Miami-Dade police Detective Alvaro Zabeleta.

The driver of the Concept vessel, Russell Bruce, 45, of Miami, contacted security personnel who then called the police. Search and rescue teams from Miami-Dade, Coral Gables, Key Biscayne, Coast Guard and Florida Wildlife Commission are searching an area comprising a three-mile radius around the dock.

Police were still calling their efforts a “search and rescue” operation, as opposed to a “search and recovery” mission in which they simply try to find a body. They had also distributed a photo of Lamar on the Internet in hopes that one of the hundreds of boaters out during the busy Memorial Day weekend sees it and can help.

“We’re trying to cross our fingers. Perhaps she somehow got out of the water,” Zabeleta said. Still, he added, “She’s still nowhere to be found.”

The two other passengers — Bruce and Alicia Nicole Bartolota, 28, of Winter Gardens, Fla. — were speaking with investigators. But few other details of the trip have emerged.

“We’re still trying to figure out what happened,” Zabeleta said.

Zabeleta hoped Lamar had a good chance of being spotted, with so many boats out for the holiday weekend. But he acknowledged that concern is building.

“The longer the hours extend, the more your hopes continue to diminish,” he said.

For Rebecca Lamar, the hours were passing like torture. And the questions kept coming.

“It’s not that big of a boat. How did they not know she was missing until they came in?” she said. “Maybe she was on another boat?”

She said the names of the other passengers were not familiar to her.