Robin Cornell and Lisa Story were found in their apartment in Cape Coral in Florida in May 1990. They had both been brutally beaten, sexually assaulted and suffocated.
On Wednesday 54-year-old Joseph Zieler was arrested for their killings after police matched his DNA to traces found at the scene when he was hauled in to custody on a battery charge.
Story, 32, was looking after Robin on May 10 1990 when Zieler is said to have attacked them.
Jan Cornell, Robin's mother who had gone to stay at her boyfriend's home for the night, returned the next day to find their bodies.
The murders were counted among famous unsolved crimes and were featured in America's Most Wanted in 2010.
Robin and Lisa, who both died from suffocation, were killed some time between 11pm and 4am before Robin's mother returned to the apartment to get ready for work.
According to NBC , she returned to find the front door locked and entered the house through the back sliding doors, which had been left ajar, to found her daughter's body in the upstairs bathroom.