Here is a full translation from a native Mexican:

Video starts

Torturer: "Look at how your son is, son of a bitch, just like the other one. Open your eyes, open your eyes (untranslatable Mexican slang word (Guey), means dumbass and used like dude is in English depending on context)"

Beating on cop with log starts

Torturer: "Open your eyes, (talking to the son). Hold him up to watch. (to another cartel member) You dumbass, what the fuck does your wife know? (to cop)"

Cop: "nothing!"

Torturer: "And if I go get her?"

Cop: "nothing, she knows nothing…"

Torturer: "You know one thing (to camera), look Tecuan, I’m going to tell you one thing, son of a bitch, nobody messes with us son of a bitch. And I’ll tell you one thing, In order to come into the plaza it will cost you dearly, first the same thing will happen to you like this piece of shit, (beats cop again) Come here and take their beating son of a bitch I’m going to tell you, here we are “Los Viagra” (The Viagras, name of the cartel) and the shit is the shit, all of these grasshoppers that are being mules giving out information, fearing any dumbass, their bitch of a mother is going to take them. (Slang Word for knife) literal translation: Iron old man. (to another cartel member)
Open your eyes boy! (to cop’s son) And if he closes his eyes fuck him up.(To other cartel members)"

Comences slicing into cop’s neck, son starts screaming

Torturer: "stand the fuck up! Look! (to cop’s son) Tecuan (to camera), this is... (Cop’s son faints) Get up! (beats unconscious boy)…(slicing continues on cop) Get up.... I will wake you up! (Picks up boy.... Boy then wakes and screams again)"

Scene switches, cop is now headless and son is laying on cop’s headless body covered in blood.

Torturer: "this is what you caused Tecuan (to camera), and we'll go get your whole family...(to boy) and you know what I'm going to do with your head, I'm going to send it to your mom dumbass...huh! Look here let them die like the rats they are, son's of bitches, (kicks son covered in cop’s blood)…little by little let them suffer the bitches, huh…huh bitch!

(Stabs boy’s chest, boy screams)

fuck!.. (indistinguishable).. What ahh!? (To boy) what ahhh!?.. What ahhh?! Son of a bitch here is a beating, it's what there is, son of a bitch, we are escalating every single day…(screaming) you are howling like a dog you soon if a bitch, of a bitch.
Grab the boy's other hand (To cartel members), hold him, hold him, hold him, hold the boy's feet, hold him good, hold him from here Guacho from here. I'm going to take his heart out, (boy tried fighting back) that's right dumbass, hold him, hold him guacho."

Camera man: "you record Diablo" (cameramen asks a guy nicknamed devil to switch places)

Torturer: "leave the rifle there Guacho, there hold him good hold him good hold him, with balls!"

Other cartel member: "straight to the point old man"

Women on Radio: "What happened, did the man come...All good over here, he comes he comes this way, that way I'll send you…"

Boy starts screaming as they commence slicing into chest/stomach

Torturer: "grab his hand, hold him…mother fucker…fuck…shit, shit fucker, hold him good, huh! Huh! Huh!…Im going to skin him alive the bitch mother fucker... Huh! Huh!"

Cartel members start howling jesting

Torturer: "the fuck out of here dumbass huh! Did you see son of a bitch, fucking dumbass mule!"

Other cartel member( most likely to the first camera man that could not keep filming): "A cigarette...A cigarette..., You should show some balls... For what they did to your nephew?!, There's the butchers'... Fuck, fuck, such a beating..."

Torturer: "Mother fucker… (heart comes out, sliced off) this is your new year's present mother fucker…(slices heart up then impales heart to now dead boy’s chest)…(to camera now) And this if for Tecuan, Tecuan and for all of you that are trying to get into the boss's plaza, sons of bitches and all you that come to the plaza the bitch of a mother will take each of you dumb assess and you'll end up worse than these dumbass dogs, you'll end up like the worse dumbass, because not Tecuan not anyone is going to come save you dumbasses. And Tecuan come here mother fucker because we're waiting and we will wait for you, we're ready to receive you dumb fuck."

Cartel members start howling again yell “puro viagra perro” (just Viagra dog!)

Cartel member: "they look real pretty there…don't they, so that all these dead fuckers show up..."

End Video.