She disappeared that fall, and her slaying has never been solved.
Cesnik's body was found in a Lansdowne dumping area more than 47 years ago. Two of the women sued Maskell, the high school and the Archdiocese of Baltimore in 1994, but the suit was dismissed due to an expired statute of limitations.
Police interviewed Maskell before his death in 2001, but never charged him.
The case is the subject of an upcoming Netflix documentary "The Keepers". Detectives have developed DNA profiles of about half a dozen suspects.
Police say they also submitted the DNA profile from the crime scene to the FBI's national database. Maskell's DNA sample was sent to Bode Cellmark Forensics lab in Lorton, Va., police said. But so far, no matches. She was last seen in her Baltimore City apartment just before running errands in the Edmondson Village. But renewed media attention forced members of law enforcement to revive the almost 50-year-old cold case, and just last week, investigators exhumed the priest's body to obtain a DNA sample. All are unsolved. Armacost said police are still investigating whether the four killings might be related.
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A DNA sample taken from the remains of a former priest does not match DNA taken from the murder scene of a nun killed almost 50 years ago.
Netflix's The Keepers is a harrowing look into the years of abuse that some students of Archbishop Keough High School claim they suffered while in attendance. The Archdiocese of Baltimore subsequently paid settlements to 13 women who alleged that Maskell molested them, lawyers for the women said.
Radakovic, who also participated in The Keepers, tells PEOPLE she wants answers to what happened to her sister almost five decades ago. "So the theory that she was killed because of something she knew in the Catholic Church was something we've been looking at". Police believe whoever killed Cesnik accosted her as she was returning from the store and forced her back into her auto.
Police said that they received results from an accredited laboratory excluding Maskell as a contributor to DNA preserved from the crime scene.
Police say, for now, their best hope in solving her murder may lie with a witness who's still alive, but has been too afraid to come forward for all these years.