Neighbor peeking into daughter’s window

We are renting a townhome in a residential suburban area. We moved in around 6months ago. Our house is a “corner” unit, meaning we share only one of our walls with a neighbor. Our backyard is not fenced in, and overlooks a wooded area. The grassy area behind the townhomes is pretty narrow before it recedes into forest.

The neighbors we share our wall with are elderly. It’s a husband and wife, and they frequently have many young kids (I assume their grandchildren) over at their house. They’re often playing in the backyard area behind my house, which doesn’t bother me at all.

I started to get a very strange feeling about the husband and wife. I tried to wave to them and say hello several times, to which they either flat out ignore or (in the case of the wife) angrily glare at me in response.

My daughter celebrated her 2nd birthday last month so we threw a small birthday party for her. The party began at around 2pm on a Sunday and ended when the police showed up at my doorstep, around 3:30pm, responding to a call regarding a noise complaint.

When they saw that it was clearly a 2-year-old’s birthday party, they apologized saying that they only arrived because it was the “5th or 6th noise related call” that they’d received regarding noise in our unit. I laughed. What noise? Kids playing? My husband and I are not extremely social people and we rarely play music. When we do, it’s usually smooth jazz while we cook!

Because that couple is the only neighbor who could potentially hear noise coming from my house, I have a strong feeling it’s them.

My 2-year-old daughter’s bedroom is on the first floor of the townhome. This morning, I went down there at 7am when I heard her crying through the baby monitor. I was wearing a sheer nightgown. As I entered the room, I saw a the husband and wife both standing on top of my flower beds, hands on their knees, peering into my daughter’s room through the 12-14” gap between her window treatments and the window sill. When they saw me, they briskly hobbled away. I’m horrified not as much because they practically saw me naked, but because it is clear that they upset my daughter.

I genuinely don’t know why they are so awful to us! We’re very unproblematic people, minus a toddler tantrum or screaming that they might hear. They have young grandchildren, though, so I’m not sure why they don’t “get it.”

My husband went over to confront them while I called the landlord. The landlord told me to capture photo evidence of this happening. My husband returned saying that they defended themselves by claiming that they were “in their own back yard.” We are furious!

I just purchased the one-way mirror window stickers for our downstairs rooms. What else can I do?

Ps: my husband suspects that they don’t like us because of our tattoos (my husband and I are both inoffensively tatted), as they appear to be extremely conservative evangelicals. Still no reason to treat us like this, however.