A sheriff says the University of Florida pre-med student charged in the weekend stabbing death of his mother had no history of mental illness or substance abuse. Polk County Sheriff Grady Judd disclosed those details at a news conference Monday. Judd says Emmanuel “Manny” Espinoza is charged with first-degree murder in the death of his mother, Elvia, at her central Florida home. He says the mother was stabbed more than 70 times when her son paid a visit from college on Saturday. Online court records showed Espinoza declined the services of a public defender but there's no indication he has hired an attorney.