Victoria Henneberry, 28, and Blake Leggette, 25, were charged Thursday in the slaying of the 26-year-old Saint Mary's University student.
They also are also accused of stealing her car.
Police confirmed Thursday they believe Saunders was killed on Feb. 13 — the day she disappeared. Police also said they believe she was killed in the apartment unit she was sharing with Leggette and Henneberry.
Her body was found Wednesday afternoon, after almost two weeks of searching, on the median of Route 2 of the Trans-Canada Highway, west of Salisbury, N.B. Forensic investigators from both Halifax police and RCMP in New Brunswick are working on the case.
Saunders was last seen in the Cowie Hill Road area of Halifax on the morning of Feb. 13. Five days later, her car was located in Harrow, Ont.
Yalcin Surkultay, who dated Saunders for 2½ years, told CBC News that when he last saw his girlfriend, she told him she was going to try to collect rent money from her roommates.
An autopsy will be performed on Saunders' remains, which were transported to the coroner services office in Saint John.
Police will not say how Saunders was killed, only that it's part of the evidence in the murder case against Leggette and Henneberry.