Two weeks ago, accused murderers Holly Harvey and Sandy Ketchum had samples of their blood taken for DNA analysis in accordance to a search warrant approved in the case, according to Lt. Col. Bruce Jordan, director of investigations for the Fayette County Sheriff's Department.

Harvey and Ketchum, 15 and 16 respectively at the time of the killings, will be tried as adults for murder, accused of stabbing to death Harvey's grandparents, Carl and Sarah Collier, Aug. 2 in their Newton Plantation home in north Fayette County, just off Ga. Highway 314.

Police said Harvey and Ketchum were in love, but the Colliers,�who were raising Holly, had instructed their granddaughter that Ketchum wasn't allowed in the home.

The DNA samples from Ketchum and Harvey will be compared to those from the alleged murder weapons: three knives confiscated by detectives, Jordan said.

Two knives were found in the vehicle the teens had used to escape to Tybee Island - Carl Collier's 2002 Chevy Silverado truck - while a third knife was found in Ketchum's back jeans pocket during the arrest, police said.

When she was arrested, Harvey had four ominous words written in ink on her arm: "Kill, keys, money, jewelry," police said. Jordan has speculated that was the to-do list for the murder and escape plan, which he said was hatched by Harvey.

Harvey was 15 and Ketchum 16 at the time of the crime, officials said.

Carl Collier, 74, and wife Sarah Collier, 73, were stabbed to death in a scene described as violent and bloody by sheriff's officials. Police said Ketchum lay in wait under Harvey's bed while the scent of marijuana was used to lure the Colliers to Harvey's basement bedroom, police said.

Harvey began the knife attack while arguing with her grandparents before pleading for Ketchum to come out from hiding and help her, police said.

At one point, Carl Collier was able to get away briefly, but Harvey chased him upstairs and killed him in the kitchen, while Ketchum killed Sarah Collier in Harvey's basement bedroom, police said.

After the killings, Ketchum and Harvey took Mr. Collier's truck and left for Griffin, where they cleaned themselves up before hitting the road for Tybee Island near Savannah, police said. The pair was arrested at a home on Tybee Island the following day by sheriff's detectives and agents of the U.S. Marshal's fugitive squad unit.

In a press conference after the killings, Jordan said he thought the teens' motive for the murder was "to gain freedom and to be able to stay together forever."

Jordan has said that Harvey was the mastermind of the murder scheme, and that she was emotionless when arrested, except to laugh at the number of law enforcement officials who affected the arrest.

Harvey's grandparents were each stabbed at least 15 times, police said.

Friends of the teens said Harvey and Ketchum had threatened to kill Carl and Sarah Collier days before the killings, but they didn't believe Harvey and Ketchum would follow up on the plans.

Ketchum has openly wept in court hearings related to the case while Harvey has kept a fairly stoic appearance. But Harvey's attorney, Judy Chidester, has said Harvey "is very frightened, very upset, very scared and very emotional."

That contrasts with the assessment of Jordan, who said Harvey was "stone cold" and emotionless when the pair was arrested.

The Colliers were raising Harvey because her mother, Carla Jane Harvey, was in prison serving time on a drug charge.

Ketchum's attorney, Lloyd Walker, has said she was raised by her father, Tim Ketchum, and her stepmother along with "a lot of support from her aunt."

Ketchum originally cooperated with police at the onset of the investigation, while Harvey did not, police said.

Given the media attention associated with the case, defense attorneys for Ketchum and Harvey are expected to file a motion seeking to have the case tried elsewhere in Georgia, but no such motion has yet been filed with the court.

Harvey would have been a freshman at Sandy Creek High School this year and although Ketchum previously attended school here in Fayette, she was most recently enrolled at East Coweta High School, according to friends.