SUMMERVILLE — Matching shell casings from earlier shootings led authorities to charge a 25-year-old man with murdering a mother and two of her children in the Archdale Forest Apartments on July 10.

The development came after an intensive investigation. Deputies responding to reports of gunshots at the apartments found Diane R. Grant, 44, her son, Jatavius DeVore, 20, and her daughter, DeAnna DeVore, 14, shot dead at the complex where they lived off Dorchester Road.

Authorities served Anthony Sanders with three murder warrants Wednesday night. The Sheriff's Office arrested him last week on a charge of firing shots into a Hunters Ridge Lane home on March 20.

"We feel very confident with bringing these charges," Sheriff Ray Nash said Thursday. "He was identified as a potential suspect early on in this investigation."

Though forensic evidence suggested a suspect, detectives were struggling to answer pressing questions about the case: Did Sanders and the slain family know each other? And why would anybody want to kill them?

For the moment, they don't know.

"We are still pursuing that," Nash said. "We don't have a definite link between him and the family that was killed."

When questioned, Sanders told detectives that he was home the night of the shootings, a murder warrant affidavit states. Yet the investigation confirmed that he had been in the complex the evening of the shooting, Nash said.

Investigators said they do not think it was a case of mistaken identity. The sheriff said there was sensitive evidence that he could not discuss, and underscored that the investigation continues to unfold "rather rapidly."

The Dorchester County Coroner's Office and the 1st Circuit Solicitor's Office assisted the effort, as did law enforcement agencies in Charleston County.

Nash said the case followed an unusual progression. Normally, detectives rely on forensic evidence to back up what people have told them. With the slaying of Grant and her children, things have unfolded in "somewhat reverse order from what we expect to see," Nash said.

"In this investigation, the ballistic information actually led us to this suspect," he said.

The Integrated Ballistics Identification System, a national database, matched .40-caliber cartridges from the Archdale Forest scene to the March 20 incident on Hunters Ridge Lane, Nash said.

The ballistics database also matched the casings to a March 4 incident on Spruill Avenue in North Charleston, Nash said. A police report describes a man seeing three men in their 20s inside a pickup truck at the corner of Spruill and Jacksonville Road.

One man in the truck stuck a gun out a window and fired about eight times in the air, the report states. The truck pulled onto Spruill and stopped; the man inside squeezed off another round before the truck sped off, the report says.

No charges have been filed, North Charleston police spokesman Spencer Pryor said.

Sanders appeared in bond court at the Sheriff's Office Summerville annex Thursday afternoon. It was largely a formality because a magistrate cannot said bail on a murder charge.

Sanders answered Dorchester County Associate Chief Magistrate Penny Merriman with a clear but soft "Yes ma'am" when she asked if he understood the charges against him and his rights. He told the judge he did not work.

He has prior convictions for possessing crack cocaine, driving under the influence and simple assault, State Law Enforcement Division records show.

Sanders said he had lived on Popperdam Creek Drive for about seven months. The address is in Forest Hills, down Dorchester Road from Archdale.

A half-dozen relatives of the victims sat in the back of the courtroom, including Marquis Grant, Diane Grant's surviving son. They declined to make a statement in court and Merriman asked members of the media not to approach them in the building.

First Circuit Solicitor David Pascoe said he will oppose bond for Sanders at a hearing before a circuit judge expected next week.