KEYSTONE HEIGHTS, Fla. – The search for a missing swimmer in Keystone Heights has been suspended.

Sean Thomas Leverette, 27, was last seen about 5 p.m. while swimming in Spring Lake, near State Road 21 at County Road 352, deputies said.

A dive team was called Friday night to search for a missing swimmer in Keystone Heights, the Clay County Sheriff's Office said. Deputy Christopher Padgett, Sheriff's Office spokesman, said Leverette and two friends were in the lake when the friends swam back to shore and realized Leverette was not with them.

Padgett said the two friends tried looking for Leverette, but when they couldn't find him, they called the Sheriff's Office, which brought in more resources to search for the missing man.

By 10 p.m., it was so dark that deputies had to use a sonar device to aid in their underwater search.

Although the dive team entered the lake, Padgett said, there's a chance Leverette might not be in the water.

“Sean may not be in the lake. We don’t know that this is necessarily a drowning. Right now, this is still an attempt to contact and an attempt to locate in regard to this missing person," Padgett said. "Let’s not just assume that he’s here. Let’s look and make sure people are being diligent themselves in possibly seeing somewhere else.”

By 11 p.m., conditions were too foggy for the dive team to continue searching, but deputies continued the search on land.

Spring Lake is surrounded by private property, and deputies spent hours going around to nearby homes,asking residents if they had seen Leverette, who is described as being 5 feet 7 inches tall, weighing 155 pounds and having brown hair and brown eyes.

The Florida Fish and Wildlife Conservation Commission was called to assist. Deputies said they plan to continue searching for as long as it takes.

Police aren't ruling out a drowning, but they're also looking into whether Leverette is still out there somewhere, alive.

"I heard somebody was missing this morning. I just didn't know it was Sean," said Keystone Heights resident Jamie Edenfield, who said that she knows Leverette. "It’s common for them to be – not show up for a couple days and be gone without saying anything."

If anyone sees Leverette, they're asked to call 911 or the Sheriff's Office at 904-264-6512.