CHULA VISTA, Calif. – A man in his 50s who was attending the Dead & Co. concert at Sleep Train Amphitheater Wednesday night died after being taken into police custody.

The Chula Vista Police Department reports that the man had been arrested for public intoxication when he became unresponsive and died.

According to police, the incident began at 7:30 p.m. when amphitheater security discovered a man, described as white and heavyset, acting in an intoxicated manner and moving from seat to seat. When they confronted him, he was unable to show them a ticket, so they tried to escort him out.

When the man tried to run from security, a brief struggle ensued and Chula Vista police officers came to assist. The man was “screaming incoherently and acting irrationally,” police said in a news release.

After a second brief struggle, he was handcuffed, arrested for public intoxication and escorted to a security office where he was evaluated by medical personnel. They determined he did not have any serious injuries.

While Chula Vista police were processing his paperwork, the man appeared to fall asleep while sitting upright in his chair. At about 8:40 p.m., an officer noticed the man had stopped snoring and had become unresponsive.

Medical personnel were called to the office, where the man was declared dead at 9:15 p.m., police said.

The San Diego County Medical Examiner’s Office is conducting an autopsy. The Chula Vista police Crimes of Violence and Professional Standard units are investigating per department policy, along with the San Diego County District Attorney’s Office.

The victim was not immediately identified.