Free Search: Keywords in legal briefs

The various companies that maintain legal briefs must have different pools of document repositories they draw from because the same search, in different brief search engines, returns various results.
Briefserve.com, describes itself as "the ultimate brief and research engine". Okay. Whatever. It searches keywords, case numbers or titles from briefs filed in state and federal courts. How many, I don't know. Here are two different results, same phrase.

The term "investigator" returned these cases from Briefserve:
Docket # Case Name Term By Request
D028719 SAN DIEGO FRAUD INVESTIGATORS V. COUNTY OF SAN DIEGO 1997
B161523 Sarkis v. California Assoc. Of Licensed Investigators, Inc. 2003
2002-0899 Mark S. and Denise R. Fridley v. Walter Horrigs, Investigator, Special Service Investigation 2002

The Brief Reporter searches by keywords, including company names, by topic or attorney. This is not a complete list of cases but, rather, selective briefs submitted by lawyers. Brief Reporter describes its service as:

a legal research service dedicated to publishing top quality legal briefs from previously litigated cases in all state and federal jurisdictions. We obtain our briefs from leading attorneys throughout the country. We add new briefs every week to our growing online brief bank.

An example result from a search by the words "private investigator":

Lee v. Industrial IndemnityGerald P. SchneeweisDefendants-Respondents' BriefCalifornia Court of Appeal Fourth Appellate District Division One4th Civil No. D023757 BrfRep-C00036731997
Private investigator of a possible fraudulent workers' compensation claim who covertly interviewed the plaintiff claimant after videotaping him to verify the claimant's identity is not liable for the negligent or intentional infliction of emotional distress. No preexisting relationship existed between the investigator and the workers' compensation claimant. The interview was not outrageous simply because the investigator failed to identify himself. The interviewer did not know the claimant had an attorney or that the claimant was psychologically unstable. Further, the interview was not so unreasonably intrusive, pervasive, or destructive that the investigator tortiously invaded the claimant's right to privacy or is liable for trespass. A trespass cause of action will support emotional distress damages only where there is either a nuisance or continuing trespass coupled with damage to real property.