"Never give-up that hope, it will prevail," said Maribel Rodriguez, the victim's daughter.
Maribel Rodriguez never lost hope.
He's charged with the shooting of Portillo point-blank in the head during an armed robbery in 1995.
It happened in a parking lot where Portillo had just left work.
She was confronted in her car and shot to death when she resisted.
In a high-tech process, scientists removed DNA from the killer's clothing recovered at the scene and checked it against the state's growing DNA database.
Detectives say the match came back to Paul Sampson.
"Mr. Sampson had a prior arrest," said Detective Lieutenant John Azzata, of the Nassau County Police Department.
Vilma Portillo was an immigrant from El Salvador and worked seven days a week to raise her eight children.