I would absolutely REFUSE to look after that stepchild again and I would disengage from her. I would also inform her father that the onus is upon him to punish his daughter and arrange care when he is working. She would also have to apologise to me but I would also let the sneaky cow AND her father know that I would NEVER trust her again.  

Where is her mother? If possible, the 16 year old brat should be sent to her other parent. I would do ABSOLUTELY NOTHING FOR HER IN FUTURE. 'ASK YOUR FATHER' WOULD BE MY MANTRA. 

I would also watch my partner very carefully as depending on his actions you may have to think about position in the relationship as his brat put your liberty at risk. 

If the home is mine, the brat would have to leave. If not I would consider leaving my partner and his rotten spawn but speak again to her father before any final decision. If you do decide to leave you do not have to inform his brat. 

I would also change my password on my email account. 

As from now, if he isn't there nor is she. The purpose of visitation is for her to spend time with her father, NOT for you to give her mother a break. 

Never be alone with her again. Not even in the same room, not in the same building.

Change all your passwords. 

He needs to find her a new home, rehome if you will. Either she is not there when he isn't or she lives elsewhere. Once she calls the police on you, it's over. No more. 

Not allowed at the house if DH isn't there. Period. 

If someone called the police on me.  They will be out of my home.  He can see her at McDonalds.   She will NEVER be left alone with me.  If DH has to go out of town, he takes her or to BM 'S 

The thing that you are doing wrong is trying to parent a messed up teen that isn't your legal/biological child. That is not to say that in your position you shouldn't have acted how you did - just that it is never going to work and will just build up her resentment of you. With a kid like this you cannot be expected to be her sole parent during the week, having to enforce some sort of order on her was always going to blow up and you are the prime target as step mother. 

Kids make up the stupidist lies. She is scared of you, so she came back to your house and wanted to get into the locked house with big old scary you??? Then petrified SD tells the police - in front of you - how scary you are.

- This is not how someone being abused acts. I'm sure the police could see this. I hope you explained the full events of the evening including her going online when she has been banned and sneaking out - is there a curfew where you are too?  - if so she is breaking that. Her previous contacts with the police would also put their suspicions up about what she told them. 

I would at a minimum install security cameras inside and outside the property. If Dad could switch jobs so he is home that would be ideal - or if your sd could stay with her mother or another relative when your husband is away that would work too.

bio and discovered you have children with your husband. This makes everything 100 times worse - if this or future events end up with a referral to CPS you are in danger of losing your kids.

So you have three options:

1) Your stepdaughter moves out of your home, permanently. No visitation. Dad can see her elsewhere. Immediately. Today.

2) You move out with your biological children. And Dad can see them separately from his time with SD. This doesn't mean you have to divorce - you just live separately for the duration. 

3) Dad takes his daughter and moves out of your home until she is launched. Again, this doesn't mean you have to divorce unless that is what you want. 

No way would I put my kids in danger because of this brat.

What you are doing wrong, IMHO, is not pushing her father to invoke forced emancipation on her. 16yos can be forcibly emancipated in some jurisdictions.

So, did the Police do anything based on her call?  I would immediately file an RO/PO against her for the risk she reprents to your reputation and also consider speaking to an attorney about a cease and decist order against her for defamation. Not sure what the legal paths are, but... I would bury her in fear and official looking letter head to the point that she would not ever want to return to your home.

I know some people will rake an SM over the coals for being the default parent in their household, but I completely understand ending up in a position where you're parenting a step kid because your partner travels. Mine was gone 70-80% of the time when my SDs were preteens. If I didn't care for them the majority of the time during his weeks, they *never* would have seen him, nor would they have had a relationship with DD or my in-laws. Life happens and when you're in a partnership, you have to do what works for your family.

That being said, I think you've reached a breaking point in your particular situation. You cannot have a child in your home who is telling lies about you to law enforcement. Especially because you have your own kids. It's simply not an option. It sucks, but the only real solution is that she doesn't come to your home unless her dad is present. This is a natural consequence for her behavior. I would let everyone know that this is your intended course of action, right away. 

What you are doing wrong? 
 

Dealing with your husbands bay bay kid while he "works" 

Your husband should either adjust his schedule to take care of his kid or give custody to someone who can (see juvenile detention center)

LOL @ her running the streets. The streets in most cities are way to dangerous for most teens and she risk getting turned out she keep playing around. 

I agree with everyone who says if DH isn't there, then your SD isn't there.  She's not at your house to see you - she's there to see her dad.  You shouldn't be responsible for her.

I provide this as a cautionary tale for locking out a teenager:  Leslie Mahaffy and her last, deadly encounter with Paul Bernardo and Karla Homolka.  WARNING - It's incredibly disturbing. 

Have your back,  SD should not see the light of day, not to mention loosing every electronic she owns or uses.  The neighbor see the police at my house over this.  Your DH tge one you love is failing you.  First leaving his DD with you, she should be at BM, if he's out of town.   Not your job to parent his DD.  She needs to be put into her place.  She a child. If she wants to live in your home she must follow your rules.   SINCE she doesn't want to follow the rules but make her own set of rules.   She's out .  as never to set foot into your home for at least six months. Then with a reall apology,  Not a fake in sorry 

'Your DH's Disnnnny daddddying is the main problem.