‘Potomac River Rapist’ Homicide Hearing Continues with Detective on Stand

A defense attorney for an elderly man charged with rape and murder called into question Sept. 19 a Metropolitan Police Department detective’s interrogation tactics while investigating the case.

Giles Warrick, 63, is charged with two counts of first-degree murder in connection with the sexual assault and death of 29-year-old Christine Mirzayan. She was found dead with multiple wounds on Aug. 2, 1998, in a wooded area on the 3600 block of Canal Road, NW. 

“Are you trained that it’s okay to mislead a person to obtain their consent,” said Warrick’s defense attorney, Stephen Mercer, to the detective who received the defendant’s consent to test his DNA.

Mercer played several audio clips of the interrogation. 

“You gave him factually inaccurate information about the length of time the test would take,” Mercer said.

The detective said he promised Warrick the findings would come in between six and eight weeks to “make the situation feel less frightening.” Mercer argued that the detective deceived Warrick to obtain his consent.

Mercer also asked the detective about his questioning of Warrick.

During the detective’s questioning, he assured Warrick that by speaking up, he would spare his family the “embarrassment” and “hardship” that this case would bring. “They are innocent people in this,” the detective told the defendant.  

Warrick is accused of being the ‘Potomac River Rapist’ who is responsible for a series of rapes in DC and Maryland between 1991 and 1998. An FBI Analyst ran the serial rapist’s DNA profile through the federal Combined DNA Index System (CODIS) and found it matched DNA from eight unsolved rape cases and one murder, court documents state.

The FBI offered a $25,000 reward for anyone with any information on the cold case. According to court documents, 100 plus tips and leads were generated. The homicide investigation continued for 20 years until Warrick’s arrest in November of 2019. 

The hearing followed an earlier motions hearing on Sept. 16.

DC Superior Court Judge Milton Lee scheduled the motions hearing to continue on Oct. 5.