Ps sued Ds for damages pursuant to 42 U.S.C. § 1983 grounded upon allegedly invalid searches of Ps' home and office. After testimony had been presented by Ps to establish the underlying facts, Ps informed the court they wished to call an attorney who, after being given 'a hypothetical of the facts that are in evidence in this case,' would be asked if he believed that a search took place in the plaintiffs' home and business. Counsel stated that the witness would then be asked: 'based on the same facts in evidence whether he believed a consent search of either the business or the residence had been taken or undertaken.' Finally, counsel proposed to ask the witness: Based on his knowledge in these areas what would constitute a proper search, or the proper documents constituting or allowing a search and would expect that he would say as follows: That if there is no search warrant, if there is no consent, if there are no exigent circumstances, that the search is illegal per se. And that would be the extent of his testimony. Ds objected in that the testimony to be given by the expert was about the law. The court allowed the expert to testify and he did so in great detail. On the basis of hypothetical questions tailored to reflect Ps' view of the evidence, the expert concluded there had been no consent given, and illegal searches had occurred. Ds appealed and the court eventually heard the case en banc.