How to detect hidden cam in my home by ex?

ok so I have an ex of whom we have a young child with....long story short I believe he has broken into my home. Nothing was ever taken of value however he had placed my camera on top of my t.v. and locked it...I had to go online to find out how to unlock it as the owners manual was missing. Also I noticed drywall dust beneath my attic which is in my daughters room. It was on her dresser. I have been followed by one of the vehicles with tinted windows that I have seen parked at his apartment.....I am being stalked. I reported and have called investigators but to no avail. At one point I saw that he had installed remote istance on my pc which was connected to his network....I found photos after that on the pc of him getting teen girls drunk. It was scary. They were clothed but kinda provocative. It makes me nervous how he is with my little one. He is in his mid thirties...so far police have done nothing. He has a cousin that lives in his apt complex who is an ex burglar....fantastic right? I think he may have installed a cam in my home but is there a way to detect it without spending a horrible amount of money?? I don't know what he is doing in my home but it is freaking me out now.