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A former school superintendent was charged today with two counts of first-degree murder in connection with the double homicide in May of a Springfield couple.

Mark Edward Porter, 53, is being held in connection with deaths of Gary and Jan Tyrrell, said Springfield police spokeswoman Lisa Cox.

Jan Tyrrell, 61, died of apparent blunt force trauma to the head, and Gary Tyrrell, 60, died of gunshot wounds, said Dan Patterson, the Greene County prosecuting attorney.

Porter, who is in the Greene County Jail, was the superintendent for the Mountain Grove School District where his assistant superintendent was Gary Tyrrell, according to the school district. The two were close friends, and Mark Porter was one of the few people allowed into the Tyrrell home, according to Greene County court documents.

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

Porter had recently asked Gary Tyrrell to loan him $250,000 but had been rebuffed, according to the charging documents. Police say they tied Porter to the crime by comparing DNA from a coffee cup that he had used to DNA left at the crime scene on a latex glove found in the Tyrrells' home.

Investigators 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 an entry for silver coins valued at about $22,000.

Porter told police that 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.

Police found no signs of forced entry to the home.

The defendant retired from school work 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.

Gary Tyrrell and Jan Tyrrell were found dead at their home at 3232 S. Greenbrier Ave. on May 1. Gary Tyrrell taught in area colleges and retired as an assistant superintendent in Mountain Grove schools after three decades. Jan Tyrrell was an Avon saleswoman and volunteer for the elderly.

Porter owns property in Ozark, according to the Christian County assessor's web site.

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.

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