BLAKE SHELTON and Miranda Lam­bert are tangled up in a shocking homicide investigation that has the country superstars gearing up for a legal battle, sources tell The ENQUIRER.

Blake has vowed to bring jus­tice to the memory of his friend and mentor, outlaw country art­ist Jerald Wayne Mills, who was shot to death in a barroom alterca­tion shortly before Thanksgiving.

Mills, the 44-year-old front man for the Wayne Mills Band, was allegedly killed in cold blood when Nashville’s Pit and Barrel bar owner Chris Ferrell shot him in the back of the head just before 5 a.m. on Nov. 23. He leaves behind a wife of more than 20 years, Carol, and a 7-year-old son, Jack.

Now Blake, 37, is calling for a full-scale homicide investigation into the bloody slay­ing.

“At first, Blake was in shock when his manager called and told him that Wayne died in a shooting,” said an insider. “But now that he’s had some time to process the news, his hurt and heartbreak is turning to seething anger.”

Witnesses say the argument erupted because Mills had been puffing away on a cigarette in a nonsmoking area of the bar. The men fought, and Ferrell shot Mills, who later died at Nashville’s Van­derbilt University Medical Center.

According to reports, Ferrell, who had a valid permit to carry a hand­gun, told police he gunned down Mills in self-defense.

“Blake can’t wrap his head around how a disagreement over smoking could lead to shots fired and someone’s life being snuffed out,” revealed the insider. “He broke down to Miranda and said, ‘I can’t let my buddy’s death be in vain. I’m going to bring justice to his memory.’”

But Blake wants more than justice says the insider – he’s also out for blood.

“Privately, he told Miranda, ‘I’d rip Chris Ferrell apart limb by limb if I had the chance.’

“Blake didn’t mince words – he thinks Ferrell is the worst kind of coward.

“Now Blaker is determined to use his fame and money to push for an exhaustive investigation into the circumstances behind the slaying.

“He’s willing to testify or serve as a character witness for Wayne – whatever it takes to help cops bring a homicide charge.

“And Miranda is fully behind Blake. She told her husband, ‘An eye for an eye, baby. I’ll support you through this night­mare.’”

Another source noted: “Blake got his start opening for the Wayne Mills Band. Wayne took a chance on him and, now, Blake feels strongly that he has to repay the favor.

“Besides spearheading a homi­cide investigation, Blake wants to do anything he can to help out Wayne’s widow and his young son.

“He’s already talking about do­ing a concert on their behalf and getting some other country music superstars, including Miranda, in­volved.”

Just hours before he was killed, Mills watched Blake and Miranda perform at a tribute concert to the late country great George Jones at Nashville’s Bridgestone Arena.

“Blake likes to act like he’s a ‘don’t-give-a-damn, good-time guy,’ but truth is, he’s fiercely loyal to those who helped him become a star,” a friend said

“Wayne was a few years older than Blake, and Wayne took him under his wing when he was just finding his feet as a performer. Even after Blake hit the big-time, he stayed close friends with Wayne and Carol.

“What hurts Blake the most is this all seems so senseless – it’s really hit him in the gut.”

The tragedy has affected Blake so deeply that the notorious party boy has been re-examining his own life.

“Wayne’s death has shown him that one night of misadventure can lead to tragedy and horrible conse­quences,” explained the friend.

“He told Miranda that Wayne’s death has served as a wake-up call and he’s going to learn to dial back his wild ways.

“He feels he not only has a respon­sibility to her, but also to Wayne’s memory.”

UDATED: An arrest has been made in the murder of country singer, Jerald Wayne Mills, Blake’s longtime pal and mentor.

Chris Ferrell, owner of Nashville’s Pit and Barrell bar was arrested for in the November 23 shooting, and Friday night  Dec. 6 was charged with second degree murder .There’s no disputing that Ferrell shot Mills, frontman for the Wayne Mills Band, a Nashville favorite, but he’s claiming it was in self-defense. 

 A grand jury was convened and decided otherwise, leading to his arrest.