Can a probation officer's report be used as justification for an arrest?

But the probation officer's report cannot be taken as justification for the arrest. There is nothing in the testimony of the arresting officer to show that the arresting officers were aware of what is contained in the report when the arrest was made. In fact, the 'several statements' that appellant had smoked marijuana may have been made after his arrest, by other arrested minors, or by other persons. The legality of an arrest must be measured by the information possessed by the arresting officer at the time of the arrest, and not by the total information gained later. (People v. Gallegos, 62 Cal.2d 176, 41 Cal.Rptr. 590, 397 P.2d 174.)