Authorities have released sketches of the suspect and are asking the community for help in apprehending the individual.
In an interview on The Early Show Friday, Miami Police Chief John Timoney said the reward for tips leading to the suspect's arrest had risen to $20,000 and many tips had been received, though most did not pan out. He said his department continued to appeal to the public for help.
"We know somebody out there - friend, relative, somebody on the block - knows this guy or suspects they know this guy," he said. "We need them to come forward."
In many serial rapist and serial killer cases, he said, a family member or friend makes the ultimate phone call that turns the police in the right direction.
The police chief said the victims range in age from 11 to 79-years-old. All of the attacks occurred within a two-mile radius in Little Havana, Shenandoah and surrounding neighborhoods.
Authorities are looking for a Hispanic male who spoke only Spanish to his victims. The police say victims described the suspect as a dark-skinned Latin male, about 5 feet, 8 inches tall, 150 to 180 pounds in weight, with short, dark hair and a mustache or goatee.
Police suspect he is an illegal immigrant because there is no record of his fingerprints in an immigration database. Timoney says the suspect is believed to have used a screwdriver as a weapon only once in his last attack.
He said police also might have identified the country from which he comes. "We're pretty convinced that at least two of the victims are adults who come from a certain Central American country," Timoney said. "And of course, they would know that language. They have convinced us that he's from that country."
In each attack, the rapist entered the home in a variety of ways. Timoney says the suspect may have been involved in other rape cases, but it is still uncertain.
"Interestingly enough," he said, "they (the victims) were all at home. This guy was able to disarm them by pretending he was looking to rent a room or home or apartment. He would engage in conversation and work his way into the home. The other interesting part is all (the attacks took place) during the daylight hours, which is very unusual."
Half of the money for the reward comes from the city of Miami and the other $10,000 comes from the Florida Department of Law Enforcement.
Also, the federal Department of Homeland Security issued a statement promising not to seek any information about illegal immigrants who cooperate with police in the hunt.