Details could be important here. The nature of the property, where it had been, how it had been taken, and why, can all play a part in the issue. And since the owners of the property retrieved it and apparently decided - at least initially - that it was not worth reporting, the police may have seen this as a civil matter now.
She can contact the agency and ask to speak with a supervisor and ask that they take a report for the theft of the property. However, keep in mind that in many CA counties, property crimes are given low to no priority right now due to a lack of resources. But, she can still ask for a report to be taken and ask that it be forwarded to the DA with a request for charges. However, she cannot compel the police to take a report nor compel the DA to pursue criminal charges.
And if the $1,200 in property was divided up among the roommates with no one roommate losing more than $950, these would be multiple petty thefts (low grade misdemeanors) and not pursued at all in some counties.
Perhaps your daughter should speak to the landlord about eviction?

