DAYTONA BEACH, Fla. -- A string of similar murders in Daytona Beach has some people wondering if there is a serial killer on the loose. Three women have been killed since December.

Now the FBI is helping to find out if they were all murdered by the same person.

All the women had similar backgrounds, but were they all targeted by the same man? Investigators said there are similarities, but are keeping a lot of the investigation to themselves right now.

"We can't get into specifics. We really want to preserve the integrity of the investigation,” said Lt. Brian Skipper, Daytona Beach Police Department.

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The victims were Julie Green, Laquetta Gunther and Iwana Patton. Green and Gunther were found in December and Patton was found a week ago.

Patton was found on Williamson Boulevard. Police said a man called in the last victim from a pay phone near Williamson Boulevard. They said he gave the location of the body and then he hung up.

Investigators said they have a few questions to ask him.

"We need to sit down with him. He's simply a witness to us right now,” Lt. Skipper said.

Police said they believe all three women were killed after accepting rides with a man they didn't know. All the publicity from the murders has prompted a lot of nervous phone calls to the Daytona Beach Police Department, especially with so many people coming into town for special events like Bike Week and spring break.

The Guardian Angels have heard about the murders. Even though the murderer, or murderers, does not seem to be targeting tourists, they are taking the time to educate women on the dangers out there.

"We found out that Bike Week was beginning. Let the women know, you gotta be alert," said William Cruz, Guardian Angels.

Police were quick to say they have not determined if this is a serial killer, or not. They said they still have a lot of investigating to do.