A reward of $10,000 is being offered by the Citizen Crime Commission, he said.
"We believe Mrs. Tong was abducted from her home in Marple Township," said Colarulo. He said she had no known enemies and was not participating in any illegal activities.
Tong, 34, was a mother of two children, ages 14 and 12, and a part-time waitress at Olga's Kitchen in the Court of King of Prussia. She and her husband, "Tony" Tong, co-owned the former Lee Heng, a Chinese restaurant in the Manoa Shopping Center.
Jennifer Tong was last seen by her husband on a Saturday morning before he went to work. She was still wearing a gold necklace, but police were unable to find her purse and $1,800 in restaurant receipts she was expected to deposit that day.
The lead detective at the time, Sgt. Joseph Maguire, is back involved with the case, said Colarulo. The Marple Township investigators who were involved have retired, but all the original files are available.
A Chinese-speaking officer from the Philadelphia Police Department is assisting with some interviews, Maguire said.
Maguire said investigators believe Tong was taken early in the day and executed in her car on the Radnor street. He said it was likely that more than one person was involved.
"We feel she was targeted for some reason," Maguire said. Investigators are resubmitting DNA samples to the state police laboratory. They will ask that the fingerprints taken at the time be reexamined.
Colarulo said police had persons of interest but would not elaborate.
"No one was ruled out as a suspect," he said.
Over the years her children periodically have contacted police to ask about the status of the case, Colarulo said.
There is no statute of limitations on murder, Colarulo added.
"We are not going to stop" investigating, he said.
Anyone with information is asked to call Radnor Township Police at 610-688-0503 x122.