Police received an anonymous tip following initial news reports about the missing girl that led law enforcement officials to stake out bus garages in Washington, Flanagan said. Radnor investigators were driving to Washington Tuesday night, he said.
Earlier in the day, the girl's father, Thomas MacMullett, said he was not angry at his daughter: "I just want her to come home."
"I haven't slept," he told reporters at the Radnor police station. "I've had to force myself to eat. I'm sick to my stomach."
Radnor police said the blond, blue-eyed teenager disappeared from her home around 4 p.m. Monday, and they suspected she was with Hareford, whose last known address was in Grottos, Va.
They said they feared Savanna MacMullett was traveling with Hareford, who was spotted near the MacMulletts' Garrett Hill house less than 24 hours before Savanna disappeared.
Hareford was stopped near the house by an officer who sensed something was amiss, police said, but he was not taken into custody because there was no evidence of any crime.
Police said Hareford was being sought on a corruption-of-minors charge, adding they "saw something that concerned us" online during their investigation of Savanna MacMullett's disappearance.
Savanna MacMullett left her house with her cellphone and some belongings.
On an online dating website, Hareford described himself as "a country boii but I have a twist," and warned that when he was angered, "most people see my hatchet man side and most are really fortunate that they didn't."
Contact Aubrey Whelan at 610-313-8112, at firstname.lastname@example.org or follow @aubreyjwhelan on Twitter.
Inquirer staff writer Mari A. Schaefer contributed to this article.