COLUMBIA, S.C. - It has been two weeks since 15-year-old Gabrielle Swainson was abducted from her mother’s home in the wee hours of the morning. Since then, the Richland County Sheriff’s Department has launched one of the most intense missing persons searches in its history.

A man who was close to the family has been charged with Gabrielle’s kidnapping.

But Gabrielle has not been found.

Police continue to hope that someone has seen something that will turn the search around.

What we know

Gabrielle’s mother, Elvia Swainson, left their North Crossing neighborhood home around 3 a.m. on Aug. 18 to go to work.

She briefly woke Gabrielle and handed the girl’s iPhone to her. The mother returned home shortly after 7 a.m. and discovered her daughter was gone. Nothing else from the house appeared to be missing except the phone. Gabrielle’s blood was found in her bedroom.

Investigators traced the phone to the home of 52-year-old Freddie Grant, a resident of Elgin, just across the Richland County line, who was involved with Gabrielle’s mother, said Sheriff Leon Lott.

Since then, Gabrielle’s blood and hair has been found on used duct tape in Grant’s house on Kelly Street. And her blood was on duct tape found in an old auto junkyard across some railroad tracks from Grant’s home.

Grant was jailed on federal weapons charges a week ago today and later charged with kidnapping. He remains in jail.

The early search

Elvia Swainson began asking neighbors if they had seen her daughter as soon as she realized she was missing.

She called the Richland County Sheriff’s Department to file a missing person report. Deputies took the report and an investigator was assigned.

The investigator determined that Gabrielle did not have the behavior patterns of a typical teenage runaway. Known as Gabbiee to her family and friends, the Ridge View High School sophomore was an honor roll student, active in her church, had just made the junior varsity cheerleading squad, sang and played guitar.

Elvia Swainson hired a private investigator, and her brother and sister-in-law came in from Atlanta. Gabbiee’s father also arrived, from Virginia, to assist in the search. Fliers were printed. A “Help Us Find Gabbiee” Facebook page was created, and Twitter users began using #FindGabbiee on their messages about her.

The sheriff’s department called the FBI and the National Center for Missing and Exploited Children for help. Those agencies brought behavioral analysts, intelligence analysts, crime scene experts and other people with expertise the local police do not have.

One of the people helping with the initial search was Grant, who Lott has described as an “acquaintance and family friend.” He had mowed the Swainson’s lawn the day before Gabrielle disappeared.

Grant’s friends said he and Elvia Swainson were involved in a relationship. Grant put his cellphone number on one of the early missing persons fliers and was seen walking the streets with Swainson as she searched for her daughter.

The investigation

In a missing person investigation, police first look for potential suspects among the closest family members.

After those people in Gabrielle’s life were ruled out, investigators looked into the next layer of family friends and acquaintances, Lott said. That circle included Grant.

Grant immediately told investigators they needed to talk to his attorney, an unusual request for someone who was a family friend, Lott said. Grant’s criminal history also led investigators to further look into where he was when Gabrielle disappeared.

FBI investigators were able to trace Gabrielle’s cellphone to Grant’s house on Kelly Street in Elgin. The large brick house, which sits on a dirt lane, is partially burned from a fire several years ago.

Authorities obtained a search warrant for Grant’s home Aug. 21. Inside, they found the used duct tape with blood and hair. Lott has not revealed other evidence they may have found.

Investigators also received a warrant that allowed them to collect Grant’s DNA.

The arrest

During their search of Grant’s home, police also found 12-gauge shotgun shells and .38-caliber hollowpoint bullets.

Because he had been convicted for possessing cocaine with an intent to distribute it, he was forbidden by federal law to have the ammunition.

A federal warrant for Grant’s arrest was issued Aug. 24, and Grant was taken into custody on Aug. 26. He is in the Lexington County Detention Center where federal inmates from the Midlands are held.

The Richland County Sheriff’s Department obtained an arrest warrant on kidnapping charges on Aug. 27. But Grant has not been served with that warrant.

Grant was appointed public defenders for both federal and state charges. Fielding Pringle, chief public defender for Richland County, has declined to comment on the case.

Lott has held several press conferences on the case. Pringle has asked a Richland County judge to issue a gag order.

The ongoing search

The day after Grant’s arrest, more than 120 police officers combed Elgin as they searched for Gabrielle.

The search first focused on the old auto junkyard in downtown Elgin was that was across some railroad tracks from Grant’s house. At one point, Kershaw County Coroner Johnny Fellers went to the junkyard with shovels, but nothing came of the dig.

Searchers also fanned out across the town, where they crawled in drainage ditches, checked underneath houses and hacked through dense brush, looking for the girl.

Lott said FBI analysts were developing potential hotspots based on evidence and tips.

Dogs, helicopters, airplanes and boats joined the hunt.

Because Grant worked as a landscaper and handyman, investigators want people who may have hired him for odd jobs to call. For example, Grant was known to drive around delivering pine straw in his pickup, and investigators want to know where he went to rake and collect the straw.

Lott has said that Gabrielle cannot be far away because Grant only would have had a few hours between the time she disappeared and when he arrived to help her mother with the search.

Other investigations

Meanwhile, two other law enforcement agencies have said that Grant is a person of interest in unsolved investigations.

Elgin Police Chief Harold Brown linked Grant to a woman who was reported missing in March. Adrianna Diane Laster, 28, of Homestead, Fla., had lived with Grant before she disappeared, and Grant is believed to be one of the last people to have seen Laster, Brown said. In April 2011, Elgin police arrested Grant on a criminal domestic violence charge for bashing Laster’s head against a wall. Grant paid a fine, the chief said.

Kershaw County Sheriff Jim Matthews said his investigators, meanwhile, are looking at Grant as a person of interest in an unsolved homicide from October 2011. Daniel Lee Wood was 36 when he was shot and killed in the front yard of a home in the town of Lugoff, near Elgin. Wood was standing around a fire with several other people when the shooting happened. Crack cocaine was found at the scene, according to earlier reports from the sheriff’s department. Matthews has not said how Grant and Wood may have known each other.

What is not known

It is not known how anyone would have known that Gabrielle had been left alone when her mother went to work in the middle of the night.

There was no sign of forced entry.

And investigators are not sure what happened to Gabrielle after she was taken from her house.

The most pressing concern for Lott has been finding the girl.

Going into this weekend, he said he held out hope that the teen would be found alive.