The Greene County sheriff says Robert O'Block, 66, and Tiffany Fleming, 27, were the two people who died at a home in Highland Springs subdivision just outside Springfield on Sunday night. They appear to have died from gunshot wounds in what likely is a murder and a suicide.

Sheriff Jim Arnott says investigators are not looking for any murderers and call this an isolated crime. Autopsies will determine the causes of death.

Arnott said O'Block lived at the home and Fleming officially lived in Rogersville, but his family members say she also lived at the home. They say the couple had been boyfriend - girlfriend for three or four years. Fleming's family members were not available to talk to reporters on Monday.

Deputies were called to the home at 3686 E. Kingswood Drive for a disturbance on Sunday night at 9:55. A woman made the call from another home. Arnott said Monday morning that he wasn't sure if she witnessed the deaths and fled, or discovered the bodies and then went to the other home. Arnott said other callers reported hearing gunshots at the home.

The sheriff says there are no signs of forced entry.

"We don't know if anyone witnessed exactly what happened inside this house," Arnott said on Monday morning. "We know that the woman who called 9-1-1 had been in the house at some point but we don't know if she called 9-1-1 before the shooting, or shortly thereafter."

Arnott said deputies were at O'Block's home several times in 2014 but said those calls involved a different girlfriend than Fleming. The calls involved domestic disturbances, alarm calls and violations of judicial orders of protection.

O'Block attended College of the Ozarks in Point Lookout and taught criminal justice there for awhile.

O'Block operated a company called Center for National Threat Assessment, Inc., at 2750 E. Sunshine St. in Springfield. That company was first registered at the Missouri Secretary of State's Office in 2004 as Management Executives, Inc., according to online records. It changed its name in 2011. O'Block listed himself as president and secretary of the corporation.

O'Block and his company are well-known to many. His employees say some 70,000 people are active members of his company, which issues credentials to people in multiple fields.

JJ Goldbourne works for the Center for National Threat Assessment.

"Our primary customers were the U.S. military and state, federal, local law enforcement entities, including several government entities, and I was tasked with implementing the training for these programs," said Goldbourne.

O'Block and CNTA made national headlines in 2012 after Public Broadcasting Service's "Frontline" investigation questioned O'Block's authority to give such credentials.

"He was what I would call an Idea man," said Goldbourne. "I could punt something to him and say, 'Hey doc, what are your thoughts on this?" and, within a short period of time, we have an idea that we can actually proceed with actually vetting it and gathering relevant information in order to make it a credible and psychometrically valid certification."

O"Block also ran American College Of Forensic Examiners International, also at 2750 E. Sunshine. "Frontline" and ProPublica also investigated that organization but he has never been been charged with a crime. A response to those organizations' investigations is attached to this report. It was written by Joshua Roberts, an attorney in Springfield who represented O'Block and his businesses.

O'Block also donated a little more than $16,000 to the gubernatorial campaign committee of Missouri Gov. Eric Greitens in 2015 and 2016.

The Greene County Assessor's Office lists the home at 3686 E. Kingswood Drive as being worth $719,000, with the land under it being worth an additional $150,000. The Assessor's Office also lists O'Block as owning business properties at 2750 E. Sunshine, 2760 E. Sunshine, 2806 E. Sunshine, and 2832 E. Sunshine.