Authorities on Thursday remained tight-lipped about a possible cause of death for 7-month-old twin girls found unresponsive in their mother's apartment the previous day in Lindenwold, Camden County.

The mother called 911 distraught Wednesday morning and said her infants had turned "purple." The Camden County Prosecutor's Office has said the babies' cause of death is "pending" as the county medical examiner performs further tests.

Authorities have not publicly identified the mother. But a friend, Markia Conover, 26, told philly.com she spoke to the mother on Facebook on Wednesday evening after sending a message of condolence.

The mother was upset and at a relative's house Wednesday night because police had not yet allowed anyone back into the Lindenwold apartment, Conover said.

The babies' mother lived in the Pines Apartments complex, just off Bilper Avenue, with the twins and two other children between ages 1 and 6, Conover said. Their grandmother also lived there, she said.

"She's a wonderful mom," Conover said of her friend. "She loved kids."