A City of Atlanta firefighter was killed Friday morning while training for a triathlon in New Orleans.

Sgt. Frank Guinn was riding his bicycle with two others, including his brother-in-law, when he was struck by a car, Janet Ward, spokeswoman for the Atlanta fire department, said Friday night. Guinn, 36, died at the scene of the wreck, which critically injured his brother-in-law, Ward said. The third cyclist was not injured.

The three bicyclists were training for the Ironman competition being held in New Orleans on Sunday at the time of the wreck. The wreck happened around 10:15 a.m., Central time, on the eastbound side of U.S. 90, New Orleans police said.

The driver of a white Chevrolet Cruze was travelling eastbound in the right lane when for reasons unknown, he rear-ended the cyclists who were also traveling eastbound, according to Officer Frank B. Robertson. The driver of the Chevrolet stopped at the scene of the wreck, which remained under investigation late Friday.

"Sergeant Guinn's brothers and sisters in Atlanta Fire Rescue are devastated at this news," Fire Chief Kelvin Cochran said in an emailed statement. "He was a dedicated professional devoted to his family."

Guinn, a nine-year veteran of the department, was stationed at Fire Station 21. He is survived by a wife and triplet daughters.

"As a Department, we will wrap our collective arms around his wife, Kim, and his beautiful girls. We ask that you keep them and Sgt. Guinn's entire family in your thoughts and prayers."

A family friend created a fundraising page for those wishing to donate.