Law enforcement sources told WPVI-TV that the man, who was expected to be charged later Wednesday, also appeared to have made a call from the area where Laura Araujo's body was found.
The body was stuffed in a trash bag, wrapped in a blanket and then placed in a duffel bag, Police Capt. James Clark of the homicide unit said. It was found early Monday by someone picking through trash dumped outside an abandoned house in North Philadelphia.
A coroner determined the cause of death was strangulation and blunt force trauma.
Araujo was a recent graduate of the Art Institute of Philadelphia. Investigators said she had been living temporarily in the building where the "person of interest" also lived.
Most of her possessions had been in her Toyota RAV-4 and were found scattered near her body.
Friends described Araujo as smart, hard-working and very religious.
She was a very nice young lady, very successful, and had a lot of good things in her future," Clark said. "It's very sad what happened to her and hopefully we'll get to the bottom of it."
Araujo had lived in New York before coming to Philadelphia to go to school. Her father, Lorenzo Araujo, a psychiatrist now living in Oklahoma, said the family has "no clue" why she was killed.