The district attorney's office says the new allegations against 57-year-old Donald Suchinsky involve a second woman.
Suchinsky is accused of using his role as a homicide detective to target his victims.
The second woman's brother had been murdered and Suchinsky was assigned to the case.
The alleged assaults happened from 2017 to 2022.
In February, Suchinsky was charged with harassing and sexually assaulting another victim, the mother of a man who was murdered in 2020.
On May 18, he was charged with Rape, Involuntary Deviate Sexual Intercourse, Sexual Assault, Indecent Assault, Terroristic Threats, and Official Oppression for his role in at least 10 alleged incidents of assault against a second victim.
Investigators think there could be more victims. Anyone with information is urged to contact the SIU at DAO_SIU@phila.gov or 215-686-9608.
Suchinsky is being held on $1.5 million bail.