Arizona Supreme Court holds that under Arizona Rule of Civil Procedure 15(c), an amended complaint naming a new defendant relates back to the original complaint if (among other things) the newly added defendant knew or should have known the plaintiff mistakenly failed to name him or her as a party in the original complaint.

A woman was injured in a car accident.  A day before the statute of limitations expired, she sued the driver’s insurance carrier pro se.  The insurer moved to dismiss, correctly arguing that an injured person has no direct cause of action against a tortfeasor’s insurance company.  Before the superior court could rule, the woman retained counsel and filed an amended complaint, naming the driver instead of the insurer as a defendant.  The driver moved to dismiss, arguing that the amended complaint did not relate back to the original complaint and was therefore time-barred.  The superior court dismissed the complaint.  The court of appeals reversed and the Supreme Court granted review. 

Under Arizona Rule of Civil Procedure 15(c), an amended complaint that adds a new defendant can relate back to the date of the original complaint if, among other requirements, the new defendant “knew or should have known that, but for a mistake concerning the identity of the property party,” the plaintiff would have brought the action against the defendant.  Following federal law, the Court explained that, in applying this requirement, courts should focus on the defendant’s knowledge, not the plaintiff’s.  The Court noted that it was overruling Tyman v. Hintz Concrete, Inc., 214 Ariz. 73 (2006) to the extent that case was inconsistent with its analysis here.  The Court also held that a plaintiff’s mistake of law as to the proper defendant is a cognizable “mistake” under Rule 15(c).

In this case, the Court held that the amended complaint related back because (1) the driver knew or should have known that the woman would have sued her if the woman had not incorrectly believed that the insurer was a proper party, and (2) the woman’s error was a mistake because it was not a deliberate strategic choice, but rather resulted from confusion over the proper defendant. 

Because the amended complaint related back, it was timely, and the Court reversed the superior court’s order dismissing the amended complaint.

Justice Lopez delivered the opinion of the court.