Almost immediately after I used a credit card online, I received a suspicious email alerting me that "an unusual sign in attempt" was made on my credit card. The email stated the credit card company would limit any further charges until they verify the account activity and provided a link where I would be required to provide "additional authentication information." The email appears to be from Chase but the signature line appears to be from American Express Customer Account Protection Services. I didn’t click on it or reply. I thought about contacting my credit card company through the website I usually use, but decided not to because I didn’t want the account to be locked when I need to travel. It’s scary because I had just used a card which I rarely use.