They want police to release body-worn camera footage and the police report.
Marquez's mother has filed a suit against the city stating her civil rights were violated in the death of her daughter.
The shooting occurred Aug. 31, 2018 when South Pasadena officers and a mental health specialist were called to the 1100 block of Fremont Avenue for a welfare check by Marquez's landlord, who was concerned about her well-being.
Police said they had been to that home on multiple occasions in the past.
A vigil was scheduled to take place Friday.