User @Kris_Mexicanese tweeted: "What if what happened in Boston at that marathon happened also at the miami heat parade ? That'd be soo cool." He sent another saying: "Boston is gonna occur again so I've heard ? RT @wsvn: Championship parade Monday at 11:00 a.m."
He later tweeted another user, indicating he was joking, saying: "This was almost funny ... Just ALMOST LOL IT'S TWITTER relax lmao it's jokes."
The FBI, Miami Police Department, and Florida Department of Law Enforcement are investigating.
"I think we've taken every precaution and then some," said Miami Police Lt. Joel Gonzalez, who will oversee security at the parade. "It's really a large geographic area. This is not a contained event in a small area, so it prevents a lot of challenges for -- not only the security and the safety on the route but the reroutes, the traffic."
Gonzalez added that the timing of the parade makes it more difficult to plan.
"This may not be the single largest event out here but it's probably the most difficult because of the challenges of the time, the lack of the preparation time," he said. "If you want to feel safe, you've got to come out and actively let us know, let us identify. We'll address the issue, but you've got to come and tell us and help us out, be our eyes and ears."
Anyone with information on the incident is asked to call the FBI at 305-944-9101.