in an area where the federal court possesses exclusive jurisdiction The fifth factor the Court must consider — whether state or federal law will apply — raises the issue of whether a federal Court can abstain when it has exclusive juris diction. The question of abstention and exclusive federal jurisdiction is unsettled. The Supreme Court has expressly declined to address it, Will v. Calvert Ins. Co., 487 U.S. 655, 98 S.Ct. 2552, 57 L.Ed.2d 504 (1978); and those courts that have confronted the issue have reached conflicting results. Compare American Disposal Services, Inc. v. O’Brien, 839 F.2d 84 (2d Cir.1988) (upholding district court’s dismissal of plaintiff s federal § 1983 action under Colorado River) with Turf Paradise, Inc. v. Arizona Downs, 670 F.2d 813 (9th Cir.1982) (<HOLDING>), cert. denied 456 U.S. 1011, 102 S.Ct. 2308,
holding that federal jurisdiction over rico claims is concurrent and not exclusive holding that a federal court improperly dismissed suit on abstention grounds where there was no concurrent jurisdiction over the federal claims holding that in the context of the federal tort claims act claims dismissed on sovereign immunity grounds are not dismissed for lack of jurisdiction but for the existence of a defense holding that when all federal claims have been dismissed the court should decline to exercise supplemental jurisdiction over the state law claims holding that federal and state courts have concurrent jurisdiction over  1983 claims