Jamming Device being used to access my Netgear Nighthawk.

Why do you suspect they're "jamming" the network? My car was being vandalized I reviewed my camera from the day before and noticed a person walking down the street and they disappeared. I rewatched the tape multiple times. I turned on the block access to my Netgear Nighthawk AC 1900 WIFI Cale Modem Router, and changed the password. 

How are they accessing it? After I did the above I reviewed the cameras the next day and noticed someone walking toward the house pointing a device at my home. They passed the house and then came back pointing the device at the house. The person stood in front of my house pointing the device. I noticed whatever the device is it was the size of a cell phone and it was flashing. The following night they did the same thing and came back again at 2:15 AM and with the same outfit on, stood in front of my car dancing moving up and down in front of my car. The following night I saw the same person on camera sitting on an electrical box beside my home. The events happen at night and I see them after reviewing my camera tape. 

What actually happens? See above. Do you loose connection? I am not sure that connection is being lost as the events usually happen while I am asleep.

Do the cameras go down? The cameras continue to function, the device they are using makes them invisible to my cameras. After doing the above I noticed my car was vandalized again and they threw dirt from a pot at my front door on the floor.

We need actual details of whats happening as well as specifics to your devices. 

Specifically they are jamming my router and targeting my cameras. I was advised by my Internet provider to hide my network, so that it is not visible to the jamming device that is being used and to report it to the police. I had already reported this and shown the police the video. They said they can't arrest someone for pointing something at my home or the other activity on camera. They have to see the person actually vandalizing my car or property. The police suggested that I use a WYZE camera that is wireless. I want to hide my network.

What nighthawk is it? Netgear Nighthawk AC 1900 WIFI Cale Modem Router

What camera's are you using? Bullet Dome 4K surveillance camera. Built in night vision 2160p wide angle lens, 4 channel NVR with built in PoE. Cability of 2160p@30FPS. The application that supports the cameras is Sibell. 

What happens to the cameras? The cameras are being jammed and I am not able to see the individual. The dirt from the pot was to let me know they still have access to my cameras after I made the changes. I believe the only way to prevent this reoccurance is to hide my network. If you can advise how to hide my network that would be helpful. 

Thank you! Sharon