AIKEN --- It has been more than three months since Ann Fox Smith was found stabbed to death in her home, and investigators still have no suspects in the Aiken teacher's slaying.

But police are hoping that evidence collected at the crime scene will yield clues that might help them identify the killer.

Lt. David Turno, spokesman for Aiken Public Safety, said the evidence was sent to the State Law Enforcement Division lab for DNA testing, but last month it was sent to the Federal Bureau of Investigation for further analysis.

"The feds have more sophisticated equipment that they can use to do different testing," he said, adding that it could take months for the results to come back.

In the meantime, investigators are still working the case, hoping for a break that will lead them to the person responsible for the 47-year-old's death, he said.

On April 25, Ms. Smith's body was found at her Whitney Drive home after she didn't show up for work at Kennedy Middle School, where she had been a special education teacher for 18 years.

Detectives don't believe the stabbing was random or committed by a stranger, Lt. Turno said.

Early in the investigation, detectives were able to exclude Ms. Smith's daughter as a suspect. After her body was discovered, investigators spoke with her estranged husband, Wilson Smith Jr., and two teenage sons, who retained attorneys and refused to speak with detectives.

Since then, Lt. Turno said, "there's been some cooperation" from the husband and two sons, but he did not say whether they have been ruled out as suspects.

Detectives have ruled out a number of friends, co-workers and acquaintances, he said.