Why am I taken for interrogation if I am not gonna be arrested?

On December 9, we had a dinner with my boss and 2 other co workers we had dinner, a couple drinks. My boss started to give me signs as well as touching me in a sexual way . Licking on my ear and asking for sexual favors. Much workers where sitting right next to me and noticed her behavior and actions towards me. She was not shy nor cared at the time . She had maybe one shot of tequila and a mix drink. We were at this location from 7:00 till 9:45. When it was time to leave she stated that I take her home. I agreed and shortly after we left area. On the way to her place she got naked and started to please her self in my vehicle. Without me touching her once we arrived to her house 2 min later. After we left, she began to climb on me and touch me progressively. I reacted and touched her in return. We moved to passenger side and I penetrated her 2 times with her consent without me ever ejaculating. I stopped and said it was not correct because she was my boss and I am her co worker. I got off her and asked her to get dressed and make her way to her house. At the time she was planning to leave my truck I advised her to put her clothes back on and began to get aggressive . She also started to talk about her sex life with another co worker of mine that she is having at the time. Once she got off my truck she left with out her clothes on and made her way to her house. She fell over some planter and scraped her foot and hit her lip. I waited till she made to front door then left her parking area. I made my way to back to my friends at the same location. All of this toon maybe 3-5 minutes and I was back with them. Soon we decided to call it a night and left home. Next days, officers take me in for interrogation they were waiting in my car garage. They question me and took me into interrogation. Same as my other 2 co workers. Apparently my boss never made it inside her home and was found by sibling semi naked and drunk she was taken to hospital. I was not arrested, though..