Alonso had worked at the store for about two years, her family said. She sent money home to her mother in Mexico, her family said.
After she was killed, Alonso's family and neighbors said she had seen the Chevere killing and had been interviewed by investigators. It is unclear how much she assisted police.
A warrant was issued for Aldea's arrest on Jan. 11, court records show.
Around 7:40 p.m. Monday, a man wearing a ski mask strode into the market, walked past two other employees, and shot Alonso four times in the chest.
The suspect fled without saying a word or stealing anything, police said.
Police have not named a suspect in Alonso's death, but had been working with federal authorities to capture Aldea since last week.
Members of the Philadelphia Police Department's Fugitive Task Force and FBI agents from Philadelphia and New York arrested Aldea in the Bronx without incident, police said.
Aldea has been arrested 11 times, court records show, including twice before he was 17 on charges of assault with a handgun, but he evaded prison time when witnesses failed to appear or because he was sentenced to probation.
On Nov. 25, 2011, he allegedly shot Chevere in the chest over a dispute at Westmoreland and Mutter Streets, police said.
Alonso's family said she had been scared that she would be targeted for having witnessed the slaying.
Anyone with information may call police at 215-686-3334.
Contact staff writer Mike Newall at 215-854-2759 or mnewall@phillynews.com.
