He had kidnapped these kids and took them to Antigua & other parents for about a year, until he was located back in the states. The kids were removed from him and returned to the custodial parent, the ex-wife. She then disappeared, although he was trying to locate her (according to his lawyer who's been making the TV rounds); if he located her, you can bet he was stalking her. At least one of the theories was that one of the persons murdered was the actual target. It may be he hadn't gotten to her yet.
And if one parent dies, the other person almost always gets custody as the surviving parent.
I suspect this angle, the robbery in AL, and the revenge shooting in Tacoma (along with other crimes he may have committed such as extortion, fraud, forgery, etc.) will be downplayed in the criminal trial. His attorneys will need to portray him as a political prisoner who was acting on his calling from Allah, blah, blah, blah.....
Malvo, on the other hand, has no such story to lean on since he is an animist and not muslim. He will undoubtedly, however, get played out as a sad case 'child' whose father abandoned him, blah, blah, blah....