Marine deputies in Florida are looking for two men, one of them a student at Colorado State University, who went missing in the Pass-A-Grille Channel near the Gulf of Mexico Tuesday evening.

The Pinellas County Sheriff’s Office says 15 students from CSU were on a charter boat off of Shell Key around 4 p.m. local time.

Five of the male students, including 21-year-old Jie Lou, went swimming off the side of the anchored boat. Due to rough winds and waves, Lou was unable to swim back to the boat.

A charter captain was helping the four swimmers when 27-year-old Andrew Dillman jumped in the water to help Lou. Investigators think the two men may have been caught in the fast moving current and were not wearing personal floatation devices.

"Our hearts go out to the family and friends of Andrew and Jie during this difficult time," Lt. Jason Holstead, the command duty officer at Sector St. Petersburg said. "We continue work closely with our partners to search for Andrew and Jie; all of us have them and their family in our thoughts and prayers."

Crews have already conducted 22 searches over 419 square miles.

Coast Guard officials said crews along the west coast of Florida responded to four separate search-and-rescue calls on Tuesday and cautioned boaters to stay vigilant during this week’s stormy weather.

CSU’s Executive Director of Public Affairs and Communications Mike Hooker issued a statement on the situation Wednesday morning.

"The safety and well-being of our students is our top priority and we are very concerned to hear of what has happened in Florida. We are gathering details and when we learn more from law enforcement, we will share information that we are able to provide. The thoughts and hope of our CSU community are for the safety of our students involved in this incident, with the missing student and charter mate and families and friends of those involved, and for the safety of rescue crews who are involved in the search."