Privately, Ramona DiGiacomo Johnstone of Woodbury struggled to cope with her only son's murder, speaking about him sometimes in the present tense. But publicly, the gregarious, 4-foot-11 woman would chat up strangers and get to know them quickly.

"She could empathize with people," said her brother-in-law Charles DePaulis. "She knew your life story in 10 minutes."

Five years after her 27-year-old son, Thomas Lennox III, a Delaware County businessman, was fatally beaten in Pennsylvania, Johnstone, 54, was fatally stabbed Monday in her apartment. It was Woodbury's first homicide this year.

Police found Johnstone about 8:30 p.m. unconscious with multiple stab wounds in her unit at Woodbury Court Apartments, 240 S. Broad St., the Gloucester County Prosecutor's Office said Tuesday.

Johnstone, who lived alone, died shortly afterward at Underwood-Memorial Hospital in Woodbury.

Johnstone's family on Tuesday struggled to figure out what happened. Johnstone's chronic obstructive pulmonary disease restricted her breathing and kept her homebound, her brother-in-law said.

"The idea of someone stabbing this frail woman . . . it doesn't compute," DePaulis said. "What would be the motive to stab a person, bludgeon a person? She couldn't have represented a threat to someone who wanted to assault her or steal something."

Authorities have not released much information about Johnstone's death.

DePaulis, who is married to Johnstone's sister, Rainy, 57, said his wife had talked to Johnstone around 5 p.m. Monday.

"Nothing that she said . . . indicated there was anything going on, or anyone was there," he said.

Johnstone's death is the county's sixth homicide this year, said Bernie Weisenfeld, a spokesman for the Prosecutor's Office. In 2011, Woodbury had no homicides and the county had three.

Johnstone never really recovered from her son's fatal beating on Feb. 24, 2007, DePaulis said.

A childhood acquaintance whom Lennox had hired to work at his car-detailing business in Norwood was convicted of first-degree murder and sentenced to life in prison.

Johnstone also had seen violence up close.

In 2004, Johnstone was a witness to an unrelated fatal stabbing outside the same Woodbury Court unit where she died, authorities said. A resident was convicted of manslaughter in the killing.

Authorities ask anyone with information on Johnstone's death to contact Detective Greg Malesich of the Prosecutor's Office at 856-384-5500 or Woodbury police Detective Tom Ryan at 856-845-0065, or text an anonymous tip to GLOTIP at 274637 (CRIMES).

Contact Darran Simon at 856-779-3829 or dsimon@phillynews.com or follow on Twitter @darransimon.