Liam Deane, a man from the U.K. who was sentenced to life in prison for killing his newborn daughter, was found dead in his prison cell just a month after starting his sentence. Officials say another inmate, John Westland, is accused of killing Deane and has already appeared in court over the incident.

Deane had confessed to brutally shaking and punching his 2-day-old daughter, Luna, because she wouldn’t stop crying. Luna died three days later from severe brain trauma. Deane was convicted of her murder and sentenced to life behind bars.

“He admitted to causing all of Luna’s injuries,” the prosecutor said during the trial, according to The Mirror. “He said he lost control because she wouldn’t settle.”

“There’s simply no explanation for what he did,” added Richard Wright, Deane’s defense attorney, during the hearing in Leeds, England.