In a civil case, can an expert testify that a police officer lacked probable cause to initiate an arrest because he relied on unreliable sources of information?

Buddress may testify that certain sources of information are generally unreliable, but he may not take the additional step and testify that an officer lacked probable cause to initiate an arrest because he relied on those sources. Accord Burkhart v. Wash. Metro. Area Transit Auth., 112 F.3d 1207, 1212-13 (D.C. Cir. 1997) ("[A]n expert may offer his opinion as to the facts that, if found, would support a conclusion that the legal standard at issue was satisfied, but he may not testify as to whether the legal standard has been satisfied.").