The new info about the car being gone from their home 4-5 is an interesting new quirk. If it's known to be that tight of a timeline, seems more likely that that info may have come from somewhere near the premises. Three options come to mind: a neighbor who saw the car leave and return, a neighbor's surveillance camera that captured same, OR someone living at the home who has relayed that info.
But the only neighbor who came forward at the outset of things was the brisket guy, who said he heard/saw "nothing" - though he was outside with his smoker about 4:15 that morning. It'd be a bit odd if another neighbor just now stepped up with this exact car info after all the ongoing media attention (though anything's possible).
A neighbor's security cam might have picked up that car leaving the garage and returning, but then what are the odds that that Acura would've left at precisely 4 and returned at 5? (JMO, but this sounds more like a 'timeframe' to me.) The camera would've recorded the exact time, wouldn't it? Another issue with this is that, though there are exceptions, most people who have security cameras have them pointed at the various points of entry into their homes (front, side, and back doors and windows)--which position would not typically capture cars traveling down the street (at least ours would not). In this particular neighborhood, the driveways are in the back, with access along the back alley - there was no house behind WM's house with a driveway/garage camera. And we've been told that the next door neighbor immediately south (across the side alley--the home directly in front of 'the tree') had his home surveillance looked at (yard, shed, etc.) with no luck.
So to me, this seems more like a time frame given by someone who was at the house. But JMO and a hunch. The fact that WM has also admitted to being up at 3:00 am, doing laundry at 3:15 am, also seems to indicate he suspects someone in the house might know and mention that he was up, perhaps even heard the washing machine at that time...or else why would WM throw 'laundry at 3:15' into such an already unbelievable story? I believe he had to account for those particular noises and events happening, specifically, at that time...which is why he didn't say the simpler, "We woke up, the front door was open, and she was gone."
So my guess is, either there's someone else (an elder? someone who can tell time, at least) also living at the home who witnessed that car coming and going during that timeframe...or perhaps it was the mother, who has begun to take the advice of her own lawyer and has *maybe* lately agreed to let LE know one or a few things (eg. 'I heard him up with the child, I heard the washing machine, I tried to go back to sleep, I got up to check when I heard the wash cycle finish, I couldn't find them but noticed the Acura was gone from the garage, I tried calling him, I went back to bed,' etc.). I'm leaning towards mom because she seems to have the most to gain from throwing a bone at LE (she wants her child back from CPS). But if there is a grandma or grandpa living with them, it could also have been their observation (maybe they woke up to some sounds and checked things out).
Tentative theoretical timeline (JMO theory):
4:00pm Friday - SM is picked up from school
-->At some point, though guessing after dark, she is possibly killed (though it's possibly not premeditated)
3:15am - WM runs a load of wash through the washing machine (trying to deal with evidence?)
*Someone, a witness in the house, is awake enough to hear this, so it is included, ludicrously, in WM's story
4:00-5:00am - the red Acura leaves the home and returns (*presumably driving away with Sherin).
*Someone, a witness in the house *may* have noticed this and finally relayed this to LE
8:00 - LE is called about her disappearance
Two points:
1) If Sherin is dead and he's trying to dispose of her body:
*The nearest access to the tollway is by driving 7.5 miles INTO the heart of North Dallas (a 14-15 min drive just to get to the major LBJ Fwy and DNTollway intersection), with its locales and shopping centers that have no shortage of surveillance cameras. IF the driver was trying to take her body to a remote location, JMO, I don't see the sense of traveling that route or getting on the tollway. If the driver wanted immediate access to a major fast route out of town, without cameras and toll tag photos, and with possibility of dumping or burying her in a less-populated region, he'd take Central Expressway (75) north, or (a bit further away) LBJ southeast. This is why I personally don't lean towards the theory that the tollway gave the investigators that tight timeframe for the car being gone from the house. I suppose his actions didn't necessarily have to be that well thought out. But I think they were, to a point. He had several hours to think and plan that night (we don't yet know exactly when she died if she died, but it was 12 hours from school pickup to Acura driving away at 4 am). I believe he is also quite smart, and smart enough to avoid the tollway, IMO.
2) If Sherin is alive:
In or out of town could've been a route taken, depending on who he was meeting up with (though I'd guess they'd still choose to avoid tollway and other cameras, because this would be two minds working and planning, not just one). Wild as it seems, a meet-up and quick transfer of child would fit the timeframe better than hiding a body. I have my doubts he could drive to a remote location AND dig a grave, in other words.
(PS. Sorry for the post length, have to leave shortly.)