I have had a stalker for 7 years and dont know what to do.?

i dont know how to stop them, the police do nothing unless i catch them or see them on my property, but they are good and i never see them, they come at night time, sit in my back yard all night, kick rubbish bins, damage my stuff outside, i got a dog in my back yard, they dont go there now but still do stuff in my driveway front yard, i see people driving ped my house 10 times a day, its a quiet street, last week i saw them turn in my street and followed i came beside their car and looked in, i didnt know them, i think it a friend of the stalker, after that i didnt see that car again, my dog barks when they are in my driveway, but he cant tell when they are on the front yard, they have gotten into my house and car, when they were both locked and done things, i have kids who are scared. they just dont care who they affect, i dont get much sleep, i want to catch them, but cant afford cameras, i cant talk to many people about it incase they think im crazy, its a weird thing to have. its gone on for so long i have moved2 times they have found me evey time, and done same things, i see there friends driving past (i dont recognise them but know they must be connected, they dont lve in my street) but i cant see the stalker, have rung police at night when they are there but the po,lice never catch them, i feel like i will have this problem forever. any suggestions?