For nearly three decades, a series of brutal sexual assaults and one murder haunted Montgomery County and the Washington DC metropolitan area. The perpetrator, known to law enforcement and the public as the “Potomac River Rapist,” was active from 1991 to 1998, leaving a trail of fear and unsolved cases. The mystery was finally brought to an end in 2019, thanks to advances in DNA technology and a collaborative cold case investigation, leading to the arrest of Giles Daniel Warrick. Warrick later died while awaiting trial.
The Potomac River Rapist was responsible for at least ten sexual assaults and one homicide, linked by DNA evidence. The crimes spanned multiple jurisdictions, including Montgomery County, Maryland, and Washington DC. The victims were women ranging in age from 18 to 58. The attacks followed a similar pattern: the assailant would often cut phone lines, force his way into homes, and cover the victims’ heads with a blanket or pillowcase. In some cases, the victims were attacked while their young children were present. The incidents can be seen below, per the FBI:
Incident 1: Monday, May 6, 1991, between 8-11 p.m. The 32-year-old victim was returning from a business trip when she was attacked inside her home in the Washingtonian Woods community of Gaithersburg, Maryland.
Incident 2: Thursday, Sept. 5, 1991, between 10-10:30 p.m. An 18-year-old babysitter was attacked inside a home in the Watkins Meadows community of Germantown, Maryland.
Incident 3: Thursday, Nov. 21, 1991, between 9-10 p.m. A 41-year-old woman was attacked in her home near Potomac Village and the downtown area of Potomac, Maryland.
Incident 4: Wednesday, Dec. 11, 1991, between 8:30-9 p.m. A 36-year-old woman was home in the Quince Orchard Knolls community of North Potomac, Maryland with her young children when she was attacked.
Incident 5: Friday, Jan. 24, 1992, at approximately 9 p.m. A 34-year-old live-in housekeeper was attacked at her employer’s home in the Potomac Grove community of North Potomac.
Incident 6: Tuesday, March 8, 1994, between 7-8 p.m. A 35-year-old woman was at home in the Highwood community of Rockville, Maryland with her young children when she was attacked.
Incident 7: Saturday, July 20, 1996, between 8:30 – 8:45 p.m., A 58-year-old victim was attacked while walking in the 4900 block of MacArthur Blvd, in the Palisades neighborhood of Washington, D.C.
Incident 8: Wednesday, Feb. 26, 1997, between 7-8 p.m. A 19-year-old woman was attacked in her Rockville residence in the Rock Creek Manor community when she came home from work.
Incident 9: Friday, Nov. 14, 1997, between 7:30-8 p.m. A 30-year-old woman was attacked in her Silver Spring, Maryland home near New Hampshire Avenue and Route 198 after returning from grocery shopping.
Incident 10: Saturday, Aug. 1, 1998, between 10:30-11 p.m. Christine Mirzayan, a 29-year-old intern, was attacked and murdered in the 3600 block of Canal Road while walking to her residence in the Georgetown area of Washington, DC.
The final and most violent known crime attributed to the serial offender was the murder of Christine Mirzayan. On August 1, 1998, the 29-year-old intern was walking home in the Georgetown neighborhood of Washington DC when she was dragged into the woods, sexually assaulted, and killed by being bludgeoned with a large rock. This shocking crime intensified the police investigation, but the case remained cold for many years.
For more than two decades, the case remained a top priority for law enforcement, but the identity of the perpetrator remained a mystery. In 2011, the FBI launched a new public campaign to generate tips, but it wasn’t until a new type of DNA analysis was used that a significant breakthrough was made. In 2019, a forensic genealogy company, Parabon NanoLabs, was able to identify a potential suspect.
Based on this new information, investigators focused on Giles Daniel Warrick, a 60-year-old man living in Conway, South Carolina. At the time of the crimes, Warrick had worked as a landscaper in the Washington, DC area, giving him familiarity with the communities where the attacks occurred. On November 13, 2019, Warrick was arrested and charged in connection with the rapes and murder.
Warrick was awaiting trial for the crimes, but on November 19, 2022, he was found dead in his cell at the DC Central Detention Facility. Officials believe he took his own life. While his death brought an end to the legal proceedings, the arrest and identification of the Potomac River Rapist finally provided a measure of closure for the victims and their families after years of uncertainty.
Press release from the Montgomery County Police Department announcing the arrest of Giles Daniel Warrick:
Detectives from the Cold Case Unit of the Montgomery County Department of Police – Major Crimes Division, are announcing the arrest of Giles Daniel Warrick, age 60, of Conway, South Carolina, for a string of sexual assaults that occurred between 1991 and 1998.
Warrick was taken into custody yesterday, November 13, 2019, in Horry County, South Carolina, on the strength of an arrest warrant. Warrick was identified as the “Potomac River Rapist” who was responsible for at least eight sexual assaults in Montgomery County, Maryland and two sexual assaults in Washington, DC., one of which resulted in a homicide.
This arrest was the result of a collaborative effort between the Montgomery County Department of Police, the Metropolitan Police Department, and the Federal Bureau of Investigation, over the course of almost three decades. We wish to thank the U.S. Marshals Fugitive Task Force and the Horry County Police Department for their assistance with the arrest.
Warrick committed a string of sexual assaults in Montgomery County where he would cut the phone lines, force entry into homes, cover the victims’ heads and sexually assault them. These events occurred between 1991 and 1998 within Montgomery County, Maryland.
Based on the investigation, a warrant was issued for Giles Daniel Warrick charging him with six (6) counts of First Degree Rape under Article 27, Section 462 of the Annotated Code of Maryland. Warrick was subsequently arrested on November 13, 2019, at his residence in the 200 block of Oak Log Lake Road in Horry County, South Carolina.
Detectives are concerned there may be additional victims in the area given the prolonged period of time that has elapsed involving Giles Daniel Warrick. Anyone with additional information is asked to contact the Major Crimes Division at 240-773-5070.
Questions regarding the homicide and events occurring in Washington, DC involving Giles Daniel Warrick should be directed to the Metropolitan Police Department’s Office of Communications at 201-727-4383.
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