Marcel Emmanuel Johnson, 21, of Bristol Township was arrested Friday after authorities say he had been linked to the crime through DNA evidence.
Johnson is charged with criminal homicide, homicide of an unborn child, arson and possessing an instrument of crime. Prosecutors are considering the death penalty.
22-year-old Ebony Talley and four-year-old R'Mani Rankins were found around 3:30 p.m. on November 25, 2013 at the Avalon Court Apartments in the 3500 block of Oxford Valley Road following a fire.
Talley, who was five months pregnant, had been stabbed multiple times. R'Mani Rankins was also stabbed and later died at St. Mary Medical Center.
Prosecutors say the fire was set to cover up the crime.
In addition, a neighbor on the day of the murder said she heard pounding on victims' door. She looked through the peephole in her door and saw Johnson go into the apartment. Moments later she heard blood curdling screams that abruptly came to a stop.
She said she knocked on the victims' door, but no one answered. So the neighbor took her dog for a walk, and when she returned the apartment was on fire.
Police say Johnson was found in the parking lot of an apartment complex with plastic bags commonly used for illegal drugs. He was arrested at that time, held on possession of paraphernalia charges, and quickly labeled a 'person of interest' in the case.
After the drug arrest police collected scrapings from under Johnson's finger nails, which investigators say contained Talley's DNA.
According to court documents, Johnson confessed to an inmate, allegedly saying that he killed four-year-old R'Mani because she was smart and he feared she could identify him.
Authorities said today that they have not been able to determine a motive.