@Kaila this whole thing has us all a bit on edge, Just great they caught him quickly. I will post updates here when I have them.
We, as tenants, have been reminded not to buzz in anyone we, personally, do not know. I mean, us long timers know "regulars" like home health aides (always in uniform, with ID). The mail carrier has a key fob to get in, while Amazon, UPS and other deliveries have to be buzzed in by the office or the tenant they are delivering to. Same with things like Pizza and other food delivery. When we tune in channel 3 on our television, we connect to the camera that monitors the foyer.
But, unfortunately stuff like this falls through cracks.
Apartment manager said she will be sending a memo to tenants to be more aware of strangers.
That would surely put everyone on edge, Marie!

It would unnerve me as well, if that happened in our building!
Someone got
into yours and took
all of those actions, even though you actually do have even more security than many of our extremely similar HUD properties.
Some of ours do have an office with a staff person during at least some regular hours, but ours does not.
We got those security cameras, in recent years, but we cannot see them on our tv. We don't see them at all.
Our camera system would be great in a crime situation, but so far,
it has been used by management, only to ID, and scold, and charge residents unexpected money,

for minor actions/mistakes, such as leaving a small item in the trash room, that is not supposed to be left there (that were allowed to be left there for many previous years)

But, back to your event this week, that is surely upsetting.
There are lots of similarities between your building and mine, with residents not supposed to let in a delivery person who is not delivering to them personally, such as a Pizza delivery, or others that are not official, but sometimes people do let those people in, knowing they are on tight pressured schedules, etc. And many of us residents cannot linger to see who might come in behind them, nor could most of us interact with anyone who might.
This upsetting incident is hopefully a wake-up call, for tenants and building managers, to be far more careful, in
your building, Marie.
And, at least your building's back-up systems did work. The alarms, the sprinkler system, the cameras , etc.....
And, Very thankfully, he was apprehended!