A fourth person is now charged in connection with the death of an inmate at the Grand Valley Institution for Women in Kitchener, Ont.

Emergency crews were called to the prison Oct. 19 to assist 19-year-old inmate Ashley Smith of Moncton, N.B.

An autopsy found Smith died of asphyxiation, which investigators said was "self-initiated," noting there were no other injuries to her body.

Travis McDonald, 36, of Cambridge, Ont., is charged with criminal negligence causing death, along with three other prison employees— Valentino Burnett of Stoney Creek, Ont., Karen Eves of Kingston, Ont., and Blaine Phibbs of Caledonia, Ont.

They are charged under a section of the Criminal Code that relates to "omitting to do anything that it is his (or her) duty to do, shows wanton or reckless disregard for the lives or safety of other persons."

Smith, who was pronounced dead in hospital, had been serving a six-year, one-month sentence for offences committed as a young offender and began serving her sentence on Oct. 17, 2003. She would have been eligible for release in November.

New Brunswick Ombudsman Bernard Richard is conducting a probe into Smith's death.

Richard said he'll examine Smith's time in New Brunswick's justice system and why she wasn't transferred to a federal women's prison closer to home. He will also be looking at the availability of mental health services for inmates.