One small consolation about the killer's parents going on the lam is that when they are found,

[Crepuscular]

9. ...

There are a lot of rural areas where you can stay pretty anonymous, especially this time of year. Break into a summer cottage in an area where there are few year round residents, use it as a base and then lay low. Assuming they have a vehicle that no one is looking for, they could have very little contact with anyone. Short drive into a large population hub, pick up fast food wearing a hat and shades and no one is likely to notice them or pick up groceries wearing a hoody, mask and some reading glasses and nobody will look twice. In Michigan, this time of year, those rural areas get a ton of transients, snowmobilers, skiiers,deer hunters,etc, so locals would not think much of someone not being local. Especially if they wear a Maga hat. They would eventually get caught but it could take awhile.