Tyler Home Center, where two people were shot by a suspected serial killer in Gaffney, S.C. (CBC)

A teenage girl who was shot while helping her father in their family's small furniture and appliance store died Saturday, becoming the fifth victim of a suspected serial killer terrorizing a small South Carolina community, authorities said.

Abby Tyler, 15, died about 11:15 a.m. at a Spartanburg hospital after fighting for her life for two days, Cherokee County Coroner Dennis Fowler said.

Tyler was wounded and her father, Stephen Tyler, 48, was killed Thursday as they worked to close the Tyler Home Center near downtown Gaffney.

County Sheriff Bill Blanton said investigators believe the five killings are linked and the search is on for a suspected male serial killer. An 83-year-old mother and her daughter were shot to death Wednesday, and a 63-year-old peach farmer was found dead at his home a week ago.

Blanton said all the victims were shot, but he would not say how the deaths were linked. The shootings all occurred within 16 kilometres of each other in Cherokee County, a rural community of 54,000 people set amid peach orchards and farms 80 kilometres west of Charlotte, N.C.

The killings began a week ago Saturday when the wife of peach farmer Kline Cash found him dead in their home.

Then last Wednesday, relatives found 83-year-old Hazel Linder and her 50-year-old daughter, Gena Linder Parker, bound and shot to death at Linder's home.

Dozens of local, state and federal investigators were assigned to the case when the killings were linked. But a day later, the killer struck again, less than a kilometre from the sheriff's office serving as the headquarters for the investigation, shooting the Tylers.

Investigators have released a sketch of the suspect, saying he is in his 40s, with salt-and-pepper hair, about 6-foot-2 and roughly 200 pounds. They think he is driving a silver 1991-1994 Ford Explorer SUV.