BOSTON (AP) — Former NFL star Aaron Hernandez hanged himself Wednesday in the prison cell where he was serving a life sentence for murder, taking his life on the same day his ex-teammates on the New England Patriots were set to visit the White House to mark their Super Bowl victory.

His death came less than a week after the 27-year-old athlete was acquitted in a second murder case.

Guards found Hernandez just after 3 a.m., Correction Department spokesman Christopher Fallon said. The onetime tight end was taken to a hospital and pronounced dead about an hour later.

Hernandez had been housed in a single cell in a general population unit at the maximum-security state prison in Shirley. He tried to jam the cell door to prevent guards from opening it and hanged himself with a bedsheet tied to a window, Fallon said.

Fallon said he was not aware of any suicide note. He said officials had no reason to believe Hernandez might take his life, and if they had had any such worries, he would have been transferred to a mental health unit.

Despite helping the University of Florida win the 2008 NCAA championship, Hernandez dropped to the fourth round of the NFL draft because of misbehavior in college.

But he was a productive tight end for the Patriots for three seasons, catching 79 passes for 910 yards and seven touchdowns in his second year to help the team reach the Super Bowl. In 2012, he signed a five-year, $40 million contract extension.

Two years later, Hernandez was unable to even watch his former team play on television while he was in prison awaiting trial in one shooting and already a suspect in another.

The team released him in June 2013, shortly after he was arrested in the killing of Odin Lloyd, a semi-professional football player who was dating the sister of Hernandez’s fiancee. He was convicted and sentenced to life without the possibility of parole.

Last Friday, Hernandez was acquitted in the deadly 2012 drive-by shootings of two men in Boston. Prosecutors said he gunned them down after one of them accidentally spilled a drink on him in a Boston nightclub.

As the jury was deliberating last week, cameras spied Hernandez blowing kisses to the young daughter he fathered with fiancée Shayanna Jenkins.

His death was “a shocking and sad end to a very tragic series of events that has negatively impacted a number of families,” said Bristol County District Attorney Thomas Quinn, who prosecuted Hernandez in the Lloyd case.

Prosecutors suggested Lloyd may have been killed to keep him quiet about the 2012 Boston killings.

Hernandez’s lawyers did not immediately respond to a request for comment.

The Patriots had no immediate comment.

The Worcester County district attorney’s office and the Correction Department are investigating the death.