Yes. And we actually have a ton of evidence (or at least knowledge of it). Here is the evidence we know of:
1. Dad claims he saw a blue child on a black and white monitor.
2. The coincidence of two people, unrelated by blood, both reacting to something bad, in a short span of time by losing their minds and committing homicide, defies reason.
3. The coincidence of those same people both committing homicide in the exact same manner -strangulation- is unlikely.
4. A father passionate enough with love for his children, to kill at the sight of them being harmed, would be desperate beyond reason to save them. But:
a. Dad failed to call 911 to try to save his children. Even if he thought they were beyond help, a parent's love is so intense they will desperately and irrationally try for help that will never come.
b. There is no account of him throwing off the mother and working desperately to revive them or resuscitate them. Hell, total strangers have performed CPR on a child's corpse in rigor. (Cooper Harris case). But a passionately loving dad didn't even try in this case?
5. The dad failed to call 911 after killing his wife in a supposed fury of emotion.
6. Dad also failed to run screaming onto the lawn for help or in anguish.
In cases of such Greek tragedy magnitude either 5 or 6 usually comes into play.
7. This entire scene - the "emotional argument", the vicious strangulation of two children, the father witnessing the incomprehensible and reacting with murderous fury and anguish - all of it was totally silent. Except for the poor dog howling that night. How do we know? Because the houses are in close proximity and neighbors mentioned hearing nothing but the dog the next day, IIRC.
8. CW did not scream or wail in anguish so great that it caused him to murder his wife. Not one report of such sounds.
9. CW supposedly lost his mind in grief and anguish. However he regained it in moments in a manner that does not comport with a true mental break. In cases we have seen where people lose it and commit murder, they are typically either wailing on the lawn and to 911 operators or they are in an apparent psychotic state- not lying about what happened, not covering it up, not able to function normally at all. See thumbnail of Julie Schenecker as an example of what this looks like.
Police interview Julie Schenecker after kids found dead
10. CW, after such an insanely, horrific Greek tragedy of a scene, calmly loaded up the bodies of his wife and children in order to conceal their deaths and dispose of them. We know this because a neighbor stated she witnessed him leaving. (No reports of wailing and she said, IIRC, the truck drove normally. So no veering, spinning of tires or other signs of lack of composure). And it's apparently on video.
11. CW, a man passionately in love enough with his kids to erupt in murderous rage when they're harmed, did not attempt to give them a burial that comports psychologically with the love and bond parents have with their kids.
Death Rituals Reported by White, Black, and Hispanic Parents Following the ICU Death of an Infant or Child
A Global History of Child Death
12. Instead he dumps them in two separate vats of oil. Not together. No way to commemorate their lives. Concealed. Discarded. In a manner that veers from any known traditional burial rite of any kind.
13. CW went to work and monitored the ring video of his house. After the horrific Greek tragedy he just endured. He went to work. And monitored the video of his front door.
14. CW left a few voice messages and sent some texts to the wife he knew was dead, thus calmly concealing what happened.
15. CW calmly called SW's friend after she came to the door and he saw her on the ring video. He asked what was going on. We know this because he stated as much and this is corroborated by the friend.
16. CW rushed home - blowing stop signs and with beating heart, according to him- when CW came to the house and expressed alarm. The first time we have heard of a hint of emotion on his part since the horrific murders of his kids supposedly by his wife and his heat of passion killing of her, occurs when he knew the authorities are about to get involved.
17. CW cooly lied to the friend about where SW was supposed to be that day and why she wasn't at home. After he lost his mind the night before. He is calm and able to work to conceal those events.
18. There is not one hint of brief reactive psychosis or drug induced psychosis in CW's demeanor and behavior since 5:15 am the morning of the deaths, nor the next day as he gives calm and detailed interviews to the media. His pupils are normal. He is not slurring speech. He does not have a vacant stare. He exhibits no delusions or paranoia. He is not showing emotional lability. (I'm no expert in psychology but have seen a few psychotic people due to psychotic breaks or drugs. You don't snap out of that fast. It's easy to research).
19. CW shows no anguish, depression, grief, concern, sadness or despair during his stoic media interviews, despite having supposedly been so deranged by his passionate love for his kids that he killed their attacker. His eyes are dry. Not red. No signs of puffiness from weeping. His face is smooth and calm. He looks well rested. No bags under his eyes. He smiles. He grins. He smirks. All with the knowledge that his insane wife savagely murdered his precious babies causing him to lose his mind with anguish. And with the knowledge that the people he loved so fiercely it caused him to kill, are at that moment rotting in separate vats of oil.
20. CW calmly and continuously lies to the media about the whereabouts of his dead wife and dead children.
21. CW systematically works with LE to track down his wife and kids. Brainstorming. Supplying numbers and addresses. Calling people. All the while knowing they are dead and decomposing.
22. CW is questioned and lies about having an affair. A motive in many murders of wives.
23. SW was pregnant. (A circumstance present in vast numbers of murders of spouses or parents by men).
24. Some people and report that CW seemed distant with his wife and kids in the weeks leading up to this monstrous event.
25. CW was not hospitalized for any reason after this tragedy.
From the CO model jury instructions:
D:01 DIRECT AND CIRCUMSTANTIAL EVIDENCE—NO DISTINCTION
A fact may be proven by either direct or circumstantial evidence. Under the law, both are acceptable ways to prove something. Neither is necessarily more reliable than the other.
E:03 PRESUMPTION OF INNOCENCE, BURDEN OF PROOF, AND REASONABLE DOUBT
Reasonable doubt means a doubt based upon reason and common sense which arises from a fair and rational consideration of all of the evidence, or the lack of evidence, in the case. It is a doubt which is not a vague, speculative or imaginary doubt, but such a doubt as would cause reasonable people to hesitate to act in matters of importance to themselves.
https://www.courts.state.co.us/userfiles/file/Court_Probation/Supreme_Court/Committees/Criminal_Jury_Instructions/2017/COLJI-Crim 2017 - Final.pdf