In the beginning, he said, the camp was small, without many problems. But lately, it has become more tense as the recession and the steady flow of former prisoners added residents.

Image The Julia Tuttle Causeway, which connects Miami and Miami Beach, has become an encampment for about 70 convicted sex offenders like Ricky Dorzena. Credit... Oscar Hidalgo for The New York Times

Under the bridge on Thursday, tents and plywood shacks competed for space with rusty bicycles, a skinny cat, and a beige lawn chair. In a sign of the camp’s bereft permanence, a yellow electrical cord attached to a generator snaked through the camp flat against the ground, pounded by countless footsteps.

“Sometimes we have harmony, sometimes chaos,” Mr. Wiese said. Mr. Dorzena, who said he served 17 months in jail for having sex with a 14-year-old when he was 18, smoked a cigarette beside him. “Right now,” Mr. Wiese said, “we have so many people here, it’s chaos.”

The police agree.

John Timoney, the Miami police chief, said that on the Fourth of July, several officers used a stun gun against a man under the bridge who, in a fit of depression, began cutting himself with a knife, apparently in a suicide attempt. Chief Timoney predicted more violence.

He said he had told city, state and county officials that the men (only one or two women live there) needed to be moved to more permanent homes, even if it meant changing one or more laws. He has gotten mostly studies in return, along with politicians accusing one another of shirking responsibility.

“It’s like a hot potato,” Chief Timoney said. “Everyone is just passing it on.”

In fact, Jose Diaz  the county commissioner who sponsored the law establishing the 2,500-foot boundary in 2005  said state corrections officials were to blame for placing sex offenders on state-owned land. He defended the county law by saying, “If I can save some kids from going through this agony, I’ve done my job.”

Gov. Charlie Crist, meanwhile, placed responsibility squarely on local governments, which have “the right to do what they feel is appropriate for the citizens that they serve.”