Two people were killed and multiple people shot as they left Club Blu Bar and Grill early Monday in Fort Myers, Florida, police said.
The shooting, which initially sent 18 people to the hospital, was not an act of terrorism, the Fort Myers Police Department said Monday morning.
Of those taken to the hospital, one died, 13 were treated and released and four were admitted, Lee Memorial Health System said.
Lee Memorial Hospital emergency room physician Dr. Drew Mikulaschek said he'd never dealt with a situation like Monday's mass shooting.
"I've been here for 17 years now and this, in terms of (gun shot wound) victims, this is the worst I've ever seen it," he said.
Police did not say if the other person killed in the shooting was pronounced dead at the scene.
The two teens killed in the attack were identified as Sean Archilles, 14, and Stef'an Strawder, 18.
Two of the victims still at the hospital were admitted to intensive care where they were listed in critical condition.
Victims' ages ranged from 12 to 27 years old, Lee Memorial said.
The shooting happened at about 12:30 a.m. Monday as parents were picking up their kids from Club Blu after a youth "Swimsuit Glow Party," Fort Myers police said.
The event was put on for children aged 12 to 17 and armed security guards were present inside and out, Club Blu said in a Facebook post.
"We tried to give the teens what we thought was a safe place to have a good time," Club Blu said on Facebook. “… As the club was closing and parents were picking their children up, that’s when all this took place.
"It was not kids at the party that did this despicable act."
Investigators believe the mass shooting at the club was connected to two other crime scenes in the city.
According to a poster advertising a "Swimsuit Glow Party" at Club Blu Bar and Grill, no ID was required at the event, which kicked off at 8:30 p.m. Sunday.
Entry to the party was $5 all night for anyone wearing a "swimsuit or swim trunk," the poster said.
"Officers arrived on scene (and) found multiple victims suffering from various levels of gunshot wounds," Fort Myers Police Capt. Jim Mulligan said. "Right now we still have a very active scene here."
Crime scene technicians could be seen in what appeared to be the club’s parking lot marking the locations where dozens of shell casings were found.
Injuries suffered in the shooting ranged from minor to life-threatening, the Fort Myers Police Department said in a release.
At one of the other crime scenes that police believe was connected to the shooting at Club Blu, vehicles had been shot at and one person received minor injuries, the department said.
The shootings happened less than a half mile from the scene of the mass shooting at the nightclub in the 2500 block of Parkway Street, police said.
One person was taken into custody at the third crime scene on Oritz Avenue between Luckett and Ballard roads, investigators said.
No other information was released on the third crime scene, which is more than four miles from Club Blu.
Police and Lee County deputies were canvassing the area looking for other people who may have been involved in the nightclub shooting.