Break-in with Key by Another Tenant

My question involves landlord-tenant law in the State of CT, and whether we have a reasonable case for a Premise Liability claim due to security negligence, or other negligence claim.

My LLC rents the first floor of a building as a business space. The 2nd and 3rd floors are rented as apartments. Shortly after our lease started, break-ins began. We estimate this happened approximately 5 times. No one witnessed anyone coming or going from the building or with the stolen items. Once we realized there was a theft, we reported it to the police, and the landlord changed the lock on the front entrance door. The police confirmed there was no sign of forced entry. There was one more break in, during which the perpetrator stole the hard drive of the security cameras we had installed that day. After that last break-in the landlord noticed that the deadbolt on a door which connects a common area for the apartments to the space we rent, was unlocked. We are 100% sure it was locked when we closed up the previous evening. After that we had him instal manual sliding bolts to every door out of our space and the break-ins have now ceased.

Our landlord has misplaced his keys on one occasion that we are aware of, and we have noticed he "recycles" door locks and deadbolts throughout the building. The landlord claims his insurance does not cover theft, but we feel the theft was only possible because of his lax security measures. Based on the unlocked door and the police assessment of no forced entry, it seems clear a key was used. It is the opinion of all involved, including the police, that the apartment tenants or their guests were the perpetrators (we have no evidence except the unlocked door, but considering what was stolen, and the lack of witnesses, it makes the most sense). The police detectives have not begun their formal investigation yet, we are on their list of cases to investigate but it may be many months. Do we have a reasonable case for a Premise Liability claim due to security negligence?

Seems to me you tell your insurance company that you believe it's the landlord's fault because of X, and let them decide whether they want to go after the landlord. You're free to sue him for your deductible and see what happens.

I forgot to mention the insurance situation. We have liability insurance in case any of our clients get injured. So this isn't covered by our insurance. The landlord told us that his insurance didn't cover our theft either. I'm sure he did not mention his negligence when he presented the situation to his insurance company. If his insurance is liability insurance, maybe they will cover the theft if they realize it was a case of premise liability due to negligence in security by the landlord. If not, we would like to know if we have a defensible case, so we can persuade him to reimburse us. Thx

This is a commercial lease. What does your lease say about locks and keys.

You assume that your landlord misplaced his keys, but offer no evidence of that. You changed or rekeyed the locks immediately after you moved in? Only two keys were out there - yours and your landlord's?

Thanks for taking a look at our question. The lease does not mention locks, but we had agreed that he would change the locks that others had keys to before we moved in. Based on that he changed the front door lock before our lease began. When we realized someone was breaking in, he changed that front door lock again. However it was another door that was found unlocked after what we believe was the last break in. That door connects our rental area with the foyer of the apartment entrance. A key is needed from the foyer side, which we have never had. It can be unlocked without a key from our side. Normally that door is kept locked and no one but the landlord has ever had the key.

We have a text message from our landlord asking if we had seen his keys that he misplaced. That is our only evidence that he misplaced his keys. He enters our unit frequently as it is his sole means to access to the basement area which has the heaters, electric panels, etc. for all tenant units.

There's a big difference between "Normally that door is kept locked" and "That door is always kept locked". If (for example) you have a resident in the building who has a habit of checking that door to see if you left it unlocked, it's pretty easy to see how a mistake by somebody in your company in failing to lock it could lead to theft. Or you could have a former employee who used a copy of the old key to get in, stole some stuff, knew exactly where the security camera hard drive would be, and unlocked the foyer door on the way out for purposes of misdirection.