Madison County Coroner Stephen P. Nonn announced Monday its conclusion in four death investigations:

* The death of Charles L. Ireland, II, 34, of Roxana was ruled accidental. Ireland was pronounced dead at Alton Memorial Hospital on July 9 after being found unresponsive and not breathing on the morning of July 7. Toxicology testing confirmed methadone and midazolam (a sedative).

* The death of Thornton W. Dalton, 103, of Collinsville was ruled a suicide. Dalton died at Anderson Hospital on Dec. 1 as a result of "combined toxicity of codeine and morphine." He had been found unresponsive at his home Nov. 27. Toxicology testing revealed the presence of morphine, codeine and temazepam.

* The death of Tonia M. Whitehead, 28, of Alton was ruled accidental due to "acute MDPV intoxication." Methylenedioxypyrovalerone (MDPV) is a synthetic central nervous system stimulant commonly marketed as "bath salts." Whitehead was pronounced dead at Alton Memorial Hospital on April 27, 2011, after being found unresponsive and not breathing at her home April 26, 2011. In addition to MDPV, toxicology testing also revealed the presence of marijuana metabolites.

* The death of Randy S. Whitehead, 30, of Pontoon Beach was ruled accidental due to "acute opiate intoxication." Randy Whitehead was pronounced dead at Gateway Regional Medical Center in Granite City on Dec. 15 after being found unresponsive at his home earlier that evening. Toxicology testing revealed the presence of morphine, codeine, alprazolam, and diphenhydramine.

It's unclear whether Tonia Whitehead and Randy Whitehead were related, according to Chief Deputy Coroner Roger Smith.