I'm briefing a 1963 Supreme Court case for a class and one of the issues described in the court decision report, and discussed in the oral arguments (audio recordings on Oyez) was the use of an informant about whom little information is provided in the materials available online (that I have found). Are there more materials available to the public, perhaps in police records, that might provide further detail about this person, or should I be able to find everything available to the public online? An assumption common to online briefs is that the man was being surveilled but the terms "surveillance" or "surveilled" were never used in the court's decision brief or during oral arguments. They say only that he was "known" for six weeks.
Assuming we're talking about the same person, the decision says in the second paragraph that the informant had been "under surveillance for six weeks." Wong Sun v. U.S., 371 U.S. at 473 (1963). It's the dissent that says he was "known for six weeks." Id. at 499.
If you still need more background on him, or someone else, there are several other potential sources for this type of information. I usually look at:
- the rulings from lower courts;
- the briefs before SCOTUS and the lower courts;
- contemporary news reports.
You could also try getting your hands on the police reports, but at 50+ years old, I wouldn't count on it.