Court papers: Longtime friends, silver coins ... murder

Gary Tyrrell and Mark Edward Porter were friends for years.

Porter was Tyrrell's boss at the Mountain Grove School District where Porter worked as the superintendent, and Tyrrell was the assistant superintendent. Porter was one of the few people allowed in the home of Gary and Jan Tyrrell which — police say — was filled with high-end items.

That trust might have helped lead to the death of the couple whose bodies were found in their home at 3232 S. Greenbrier Ave. on May 1.

Porter, 53, who was arrested Friday, is charged with two counts of first-degree murder in connection with the killings.

Jan Tyrrell, 61, died of apparent blunt force trauma to the head, according to the charging documents. Gary Tyrrell, 60, a retiree who dealt in precious metals and gemstones, apparently died of two gunshot wounds.

Porter was recently rebuffed by his longtime friend when he asked Gary Tyrrell to loan him $250,000, according to the charging documents. Police say they tied Porter to the crime by comparing DNA from a coffee cup — obtained by an undercover officer from Porter after the killings — to crime scene DNA left on a latex glove found in the Tyrrells' home.

Investigators also say they also found that Porter sold $18,531 in silver coins a day after the couple's bodies were found. Documents found in the Tyrrell home showed a log entry for silver coins valued at about $22,000.

Interviewed by police, Porter told an officer he was supposed to meet Gary Tyrrell on April 30 at a McDonald's but that Gary Tyrrell never showed up. Porter told police he then drove to the Tyrrell home but was unable to contact anyone in the house.

A walk-in safe in the basement had scratch marks on it as though someone had tried to break in the safe, according to the charging documents. Other high-end items in the home were left untouched.

Police found no signs of forced entry to the home.

Gary Tyrrell worked for Mountain Grove until his retirement in 2005. He was a teacher, principal and administrator in the Mountain Grove district.

The defendant left the educational field in 2008. After Mountain Grove, Porter went to Wright City School District near St. Louis where he retired, according to the school district.

"People in the community liked him," said Chris Gaines, the current superintendent.

Porter owns property in Ozark, according to the Christian County assessor's web site. The documents list his address as Ozark, too.

Porter's online profile on LinkedIn lists him as a graduate of Evangel University where he studied music education.

He also has studied at Missouri State University and the University of Arkansas.

Evangel's website lists him as an adjunct professor of music, teaching a class in music appreciation French horn. An Evangel spokesman said Porter last taught in 2013 in an online class.