He beat his wife to death on an Alaska cruise in front of their children. Here's how long he'll spend in prison.

A Utah man who murdered his wife on an Alaska cruise with their family will head to prison for three decades.

Kenneth Manzanares appeared in federal court before Judge Timothy Burgess this month after he pled guilty to second-degree murder for the death of Kristy Manzanares. His daughters and other family members were also present in the courtroom.

Kenneth and Kristy argued in their cabin aboard the Emerald Princess on the night of July 25, 2017.The couple’s argument started because of Kenneth Manzanares’ behavior earlier in the evening. Kristy asked Kenneth to leave the ship and return to Utah, alone, according to reports.

Two of their daughters watched helplessly from a connecting balcony to their parents’ room as their father continuously pummeled their mother’s face with his fist.

Frantic, the daughters alerted the crew.

"One of the little girls from that room came running out, calling for help, that her parents had been in a fight. She sounded pretty desperate, but the crew came up as quickly as they could," said Chris Ceman, who had been on the ninth floor opposite the Manzanares’ cabin, according to CBS News.

Before security arrived, Kristy’s brothers and father, who were also on the cruise, saw Kenneth Manzanares attempting to drag his wife’s body towards the balcony. One of her brothers grabbed ahold of her ankles and pulled her back into the cabin. But, Kristy died from the injuries in the beating.

Kenneth Manzanares was immediately placed under arrest and in federal custody because the ship was in U.S. waters at the time of the incident.

Prosecutors asked for a life sentence and described Kenneth Manzanares as a habitual violent and hot-tempered individual who admitted to restraining his wife and punching holes in walls at their home.

In contrast, Jamie McGrady, a federal public defender and Manzanares’ defense lawyer, claimed his actions were because of an undiagnosed medical condition. In a court filing, McGrady asserted the defendant suffered from brain abnormalities consistent with injuries from years of playing contact sports.

Furthermore, she stated Kenneth Manzanares had been undiagnosed with bipolar disorder, combined with alcohol and prescribed medication, which caused the violent episode during the cruise.

In a rebuttal, prosecutors claimed Kenneth Manzanares knew what he was doing, and his actions were intentional. They described Kenneth Manzanares' motive for the murder as triggered when his wife demanded his leave from the cruise ship and wanting a divorce.

McGrady pleaded with the court for leniency on behalf of the defendant’s children. Though they hold their father responsible for their mother’s death, they understood his impairments played a role. They asked the court to consider they have already lost one parent and should not lose the other.

The defense asked the court to sentence Kenneth Manzanares to seven and a half years in prison.

Burgess agreed with the prosecution that Kenneth Manzanares should be held culpable for the death of his wife, which had been committed in the presence of the children. He also highlighted the failure of the defense experts to show what factors led to the crime.

Burgess sentenced Kenneth Manzanares to 30 years without the possibility of parole and five years supervised release.

“No excuse can justify the savagery committed by this man, who will now spend the next three decades behind bars. The FBI worked tirelessly, with the support of our partners, to seek justice for Kristy – a beloved mother, daughter, sister and friend.  While justice has now been served, the lasting impact and trauma this man inflicted on Kristy’s family can never be erased. Our thoughts are with Kristy’s family and her home community.” said Robert Britt, Special Agent in Charge of the FBI Anchorage Field Office, according to the U.S. Attorney’s Office.

Manzanares’ plea allowed for an appeal based on the reasonableness of the sentence, McGrady told AP News they would seek to appeal his case.