May offend Spanish to English Law/Patents Law (general) Vulgar slang / Mexico

This phrase occurs in an eyewitness account of a murder, and is spoken by one of the killers to the victim, who is shot dead just minutes later.

What makes this confusing is that the victim's mother (one of the persons recounting the events) was present at the scene being rrecounted. However, I do not think that the utterance here is a threat toward the victim's mother, but toward the victim himself.

Other verbal threats made toward the victim according to the account provided:
"TE LLEGO TU HORA HIJO DE TU CHINGADA MADRE"
"TE VAS A TRAGAR TUS RISAS"

Many thanks.