Statement Analysis has some thoughts on this and they don’t look good for the mother.
http://statement-analysis.blogspot.com/2017/11/north-carolina-missing-3-year-old.html
http://statement-analysis.blogspot.com/2017/11/missing-mariah-mothers-language.html
http://statement-analysis.blogspot.com/2017/11/missing-mariah-is-mother-cooperating.html
If boyfriend is a meth dealer he probably sold her in a drug trade.