Judge Peter Gallagher reviewed a doctor's report and found Regina Renee Johnson, 56, was unable to understand the charges against her and could not assist in her defense at trial.
Johnson will be sent to Patton State Hospital in an attempt to restore her competency.
The woman was arrested on June 2 in connection with the slayings. 56-year-old Reuben Johnson was retired from the Navy and working as a security guard, and Aaliyah Johnson was a freshman at West Hills High School.
According to Deputy District Attorney Claudine Ruiz, the defendant called family members out-of-state, informing them that her husband and daughter were dead, and they relayed the information to the San Diego Police Department. Officers sent to the Johnson condominium found Reuben Johnson's body in an upstairs hallway and his daughter face-down in her bedroom, she said.
Both had been shot in the head, and Reuben Johnson also had a gunshot wound to the upper body, according to Ruiz. She said both bodies were in a state of decomposition when discovered.
A 9 mm handgun registered to Reuben Johnson was found in the residence, Ruiz said.
The slayings could have been committed as early as May 30, three days before the gruesome discoveries, Ruiz said..
A motive was not revealed, but Regina Johnson reportedly had lost her financial services job recently. Investigators said there were no previous reports of violence in the Johnson family, and the defendant had no criminal record.-City News Service contributed to this report.