Nope. The law encourages department to establish policies that ENCOURAGE arrests, but no such requirement is imposed. The only one that leaps to mind is with regards to a domestic violence restraining order. The language under PC 836 for those states that an officer "shall" make an arrest when there exists probable cause.
Huh? What law?
Regarding not arresting someone when evidence shows doestic violence occurs and police do not act it can qualify as involuntary manslaughter.
Involuntary manslaughter differs from Penal Code 187 PC murder in that it involves an unintentional death.2
California Penal Code 192(b) PC defines "involuntary manslaughter" as an unlawful killing that takes place
2.during the commission of a lawful act which involves a high risk of death or great bodily harm that is committed without due caution or circumspection.3
Involuntary manslaughter does not apply to acts that you commit while driving a car (those are covered by California's vehicular manslaughter laws, discussed under Section 4. Related Offenses).4
Let's take a closer look at some of these terms to gain a better understanding of their legal meanings.
Without due caution and circumspection
The phrase "without due caution and circumspection" is basically synonymous with California's legal definition of "criminal negligence." It is an act which is "aggravated, reckless and flagrant and which is such a departure from what would be the conduct of an ordinary prudent, careful person under the same circumstances as to be in disregard for human life, or an indifference to the consequences of such an act."7
Criminal negligence means that the death was not the result of inattention, mistaken judgment or misadventure. But rather it was a reasonably foreseeable consequence of the aggravated, reckless or negligent conduct.
Example: In People v. Conrad Murray…the pending case against Michael Jackson's doctor…the Los Angeles District Attorney's Office charged Dr. Murray with violating Penal Code 192(b) PC California's involuntary manslaughter law for allegedly administering lethal doses of an anesthetic (propofol) to Jackson while treating him for insomnia. And although this case is still ongoing, it serves as a good example, since it is currently one of the most famous cases dealing with California's involuntary manslaughter laws.
In their complaint, the D.A. stated that "Dr. Murray did unlawfully kill Michael Joseph Jackson by acting without due caution and circumspection". Prosecutors will attempt to prove that Dr. Murray acted with criminal negligence when he administered such a large dose of the anesthetic…an anesthetic that they contend is used in preparation for surgery, not as a sleep aid (which is why it was being used). The D.A. will argue that a reasonable doctor in the same situation would not have authorized the same quantity of the drug.
Currently, Dr. Murray's California preliminary hearing is scheduled for January 4, 2011.8