A Springfield man died while in the custody of police in Holyoke on Saturday.
The Hampden District Attorney's office says Daniel Allende was picked up for OUI and drug possession charges and went into medical duress while in custody.
The D.A.'s office says first responders immediately initiated CPR and used a defibrillator, but that Allende was pronounced dead a short time later at Holyoke Medical Center.
The death is being investigated by state police and the Chief Medical Examiner.