Liam Deane, a British man serving a life sentence for the murder of his 2-day-old daughter, was found dead in his prison cell just one month into his sentence. Authorities allege that Deane was killed by fellow inmate John Westland, who has since appeared in court in connection with the death.

Deane, 22, had confessed to violently shaking and punching his newborn daughter, Luna, after she wouldn’t stop crying. Luna suffered traumatic brain injuries and died three days later. He was convicted and sentenced to life in prison for her murder following a trial at Leeds Crown Court in England.

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

Richard Wright, Deane’s defense attorney, acknowledged the severity of the crime, stating, “There is simply no explanation for the defendant’s actions.”

Westland, the inmate now facing charges related to Deane’s death, has not yet entered a plea. The investigation into the incident is ongoing.