A gunman killed his wife outside the South Florida restaurant where she worked, then targeted women inside and shot dead three others before committing suicide.
Police said 38-year-old Gerardo Regalado by-passed at least two men when he fired at the women inside. Three women were in a critical condition, Detective Eddie Rodriguez said.
"He went straight for the women," Mr Rodriguez said.
Regalado is the half-brother of former New York Yankees pitcher Orlando "El Duque" Hernandez.
The shooting on Sunday night began in a car park outside the Yoyito Restaurant in Hialeah, where Regalado, of Coral Gables, was seen arguing with Liazan Molina, Mr Rodriguez said.
According to Florida marriage records, the couple married in 2007.
Police said Regalado shot dead Ms Molina, 24, then entered the restaurant and fired at six women inside.
Regalado drove off after the shooting and officers found him dead a few streets away, with the same weapon used in the restaurant shootings, Rodriguez said.
People inside the house where Regalado and Ms Molina lived refused to answer the door. A person who answered the phone identified himself only as a family friend and said the family did not want to talk.
Hernandez's agent, Mike Maulini, told the Spanish-language newspaper El Nuevo Herald that the family did not know what caused Regalado to shoot the seven women.
"This has taken everyone by surprise," he said.
Regalado came to Miami from Cuba in 2006, he said.
"We do not know what might have happened. He was a good kid. Since he arrived he has tried not to depend on his brother and do his own work," Mr Maulini said.
In a statement, Hernandez's family offered their condolences to the families of the seven women.
"It is with great pain that we reach out to everyone affected and offer our prayers in this time of sorrow," the statement said.
It was not immediately clear if all the women shot were restaurant employees or customers. The shooting began at 10.15pm, shortly after the restaurant had closed.