I am accussed of stealing from an Apt. They have video of me going in the Apt but I am working, should I get a lawyer?

I work for a fire alarm company, and we do annual inspections of the fire alarm system. This includes going in to Apt's and checking the speakers of the fire alarm in the Apt's. During the inspection, A problem came up in an Apt while I was testing it. Throughout the inspection, a guard was walking with me, sometimes he would go in the Apt with me other times he would just open the door and let me in. When we finished going through and checking all the Apt's, I told the guard that I needed to go back in to the Apt that came up with a problem that I mentioned above. He told me that the door was open and I can go in. That was my mistake, I should have told him he needs to go with me, in which I normally do, but for whatever reason I did not and I agreed to just go myself. That is where they have a video of me going in this Apt by myself. A couple of days later, the Apt Bldg calls my work and says they have me on camera going in the Apt and a Nintendo DS is missing after that. The video supposedly only shows me going in the Apt by myself and me walking out and I have nothing, but this Nintendo DS is small enough that it could be in my pocket. They also said that I looked suspicious going in or out of th Apt because I was looking up and down the hall. I did not take anything from this Apt, I merely went in to troubleshoot a problem that I fixed. The other unfortunate thing is that I did not document this problem, so I have no proof that there was a reason for me going in the Apt. I am a bit concerned that I can be falsely charged for this and I wonder if I should get a lawyer or if there is something I should be worried about at all?