Can someone tell me why this method is going into an infinite loop?

So it seems this method is going into an infinite loop if the if(printLibraryNumber.equals(borrowersArray[index].getLibraryNumber() statement is true, and I have no idea why.

public boolean printBorrower(String printLibraryNumber)
{
   int index = 0;
   boolean isPrinted = false;
   while(index < currentIndex)
   {
       if(printLibraryNumber.equals(borrowersArray[index].getLibraryNumber()))
       {
           borrowersArray[index].printBorrowerDetails();
           isPrinted = true;
       }
       else
       {
           index++;
           isPrinted = false;
       }
   }

   if(isPrinted == false)
   {
       System.out.println("Borrower with library number " + printLibraryNumber + " not found.");
    }

   return isPrinted;
}