Killer of beloved Miami Herald employee is executed in Florida 25 years after her murder

Miami Herald

08-04-2025

The man who carjacked, sexually assaulted and murdered a beloved Miami Herald employee in 2000 was executed Tuesday evening.
Michael Tanzi, 48, died by lethal injection at 6:12 p.m at Florida State Prison in Raiford, about 45 minutes north of Gainesville. He was on Death Row for more than two decades.
On April 25, 2000, Acosta, 49, was abducted by Tanzi, a 23-year-old Massachusetts drifter who asked Acosta for a cigarette, punched her and threw her into her Plymouth Voyager van as she was reading a book on her lunch break at the Japanese Rock Garden on Watson Island.
Tanzi tied up Acosta in the back of the van and headed to Key West, stealing her money from ATMS along the way after threatening her with a box cutter to get her bank account password. He then sexually assaulted her before strangling and dumping her body in thick mangroves near a public boat ramp in Cudjoe Key, 20 miles north of Key West.
A Monroe County judge sentenced Tanzi, who confessed to Acosta's murder, to death in 2003.
Hours before his execution, Tanzi was offered a final visit, meal and shower. He requested pork chops, prison officials say.
READ MORE: A Herald employee was brutally murdered 25 years ago. Her killer is set to be executed
Acosta, a 25-year Herald employee, was a supervisor in the Herald's paper make-up department. Former coworkers said she had a gentle — but firm — hand as she dealt with editors and advertising department representatives pushing her to give them more space on the page.
Acosta would often spend her lunch break reading at the garden, which was a short ride over the MacArthur Causeway from the Herald's former headquarters off the Causeway, overlooking Biscayne Bay. But she always returned precisely an hour later, knowing she had deadlines to meet.
When she didn't return from her break, several of her co-workers quickly alerted the Herald's executives, who contacted Miami police, and her bank. Their efforts helped detectives arrest Tanzi two days later in Key West as he was about to get into Acosta's van.
'It makes me want to cry,' her coworker and close friend Carolyn Green said. 'That's why I haven't spoken about it. Janet was the nicest person you'd ever want to meet.'
Met Jimmy Carter at Habitat for Humanity
From a young age, Janet's niece Jennifer Andrew looked up to her aunt's eccentric and artistic personality.
She also loved the outdoors, regularly volunteering at Shake-A-Leg, the sailing program in Coconut Grove that works with individuals with disabilities, her family said. Before joining the Herald, Acosta taught English at sea and traveled across the world.
Acosta once met former President Jimmy Carter while building a home in Miami with Habitat for Humanity.
Andrew said they spread Acosta's ashes — and later her dog Murphy's — in the ocean.
'A fledgling serial killer'
Tanzi ambushed Acosta to get to Key West. He had traveled from New York City with two people who dropped Tanzi off in Miami after an argument.
Tanzi admitted to police to scouting for a remote location to kill her and came upon the secluded spot in Cudjoe Key. He confessed to murdering Acosta in what police described as a 'matter-of-fact' manner, asking for cigarettes, pizza and a soda and occasionally smiling and laughing.
Miami Police Lt. Carlos Alfaro called him 'a cold-blooded animal' at the time of Tanzi's arrest. During the taped confession, Tanzi explained why he killed Acosta:
'If I let her go, I was going to get caught quicker,' he said, the Herald reported. 'I didn't want to get caught. I was having too much fun.'
Tanzi also confessed to another murder: the Aug. 11, 1999, killing of 37-year-old mother of two Caroline Holder in Brockton, Mass. Holder was found strangled and stabbed in the throat at a coin laundry, just eight months before Acosta was killed. Tanzi was never charged with Holder's murder.
'What we have here is a fledgling serial killer,' Miami police detective Frank Casanovas told the Herald in 2003.