Ask Whitley Strieber discussion

At the very beginning of this book the detective wakes up to find his wife missing. It's 12.40 am we are informed.
A little while later, he and his police friends discover that the alarm system was switched off at 3.32 am, then turned back on at 3.33 am. Leading them to believe she left the house or was kidnapped 3 hours after the husband woke up ?
I am confused by the timeline here. Whitley Strieber

The book in question is Alien Killer, published in 2013.