After being forced to the river's edge, Fritz's boyfriend managed to swim to the West Virginia shore, where he called police, but Fritz was not as lucky: Her nude body was pulled from the Potomac River on March 13, 1979.
Cook, who pulled Fritz's case file in the spring, said in May that sexual assault was not listed in the original case file, "but it was also 1979 and things are different now."
Cook said clothing found on the bank of the river and in the vehicle were tested but, "out of the items examined, there was nothing of evidentiary value."
Fritz's case is among 10 cold cases in Washington County and among more than 100 cold cases in Maryland, Cook, local investigators and a detective have said.
Cook, who is one of two cold-case investigators with the Maryland State Police homicide unit in Columbia, Md., said he was in the process of investigating a few cold cases outside Washington County, but has plans to investigate the unsolved death of 15-year-old Loraine Zimmerman at the end of this year.
Zimmerman's body was found on April 14, 1984, under large pieces of cardboard weighted down by rocks 3.6 miles south of Boonsboro and about 70 yards south of Reno Monument Road. She had been beaten, raped and strangled.
Zimmerman was last seen leaving her aunt's house in downtown Hagerstown eight days before her body was found.
Cook said that police likely will reinterview witnesses in Zimmerman's case toward the end of this year.
"We have the file pulled," he said.