My neighbor John has been collecting gold coins for the past 20 years. Upon buying a coin, he would place it in the safe deposit box he and his wife, Caitlin, rented at their bank.

John put the gold there for an obvious reason: security.

A thick steel door safeguards hundreds of stacked metal boxes. The boxes are protected by a two-key system.

The bank gives you one key to use in combination with a “guard key” held by a bank employee. In addition, you must provide personal identification and sign the register every time you visit the bank to access your box.

If your bank uses a keyless system, you will instead be asked to scan your finger or hand.

A few weeks ago, Caitlin decided to go to the box, count the large stack of coins and calculate their value (roughly estimated at $100,000). She and John are retired now and thinking about tapping into their nest egg.

It had been at least five years since either of them had checked the box.

After the bank employee took it out and left the vault, Caitlin opened it: It was empty.

Disbelief turned into anger. She summoned the bank employee and asked to speak to a manager. The manager could provide no explanation as to the whereabout of the box’s contents.

Bank records confirmed that John and Caitlin had last visited in 2014; no one had been logged in since then.

This began an eye-opening set of events.

The couple contacted the police, who told them that without an inventory or any proof the gold coins were in the box, they could not help.

Even worse: Their rental agreement, the bank told them, provided no insurance or liability for the contents of their box. Unlike the cash you have in your bank account, the contents of a safe deposit box are not covered by FDIC insurance.

They consulted an attorney. The attorney told them he would take the case only on an hourly fee basis, not on contingency, because in almost every case the law does not hold the bank liable, per the rental agreement the box holder signs. They passed.

How could this happen, they wondered.

There are a few reasons why a safe deposit box may be empty.

Sometimes owners remove items and forget they did so.

Sometimes they allow a family member to “sign on the box,” granting them the same rights as the box owner. A family member may have taken items without telling the box holder.

Lastly, if a box holder has a long-term unpaid bill but there are items in the box, the contents are documented, removed and shipped to a holding facility and ultimately, if not claimed, sent to the state controller’s office.

John and Caitlin say none of these situations pertains to them.

There are more than 25 million safe deposit boxes in the U.S. Police reports regarding thefts have been filed on fewer than 1%, but it does happen.

John and Caitlin appealed to the office of their bank’s headquarters, but their request for reimbursement was denied.

They wanted to share their story to alert other box holders of facts they learned the hard way: Banks do not take responsibility for the contents of a rented safe deposit box; the holders of the box assume all the risk.