LOCK HAVEN, Pa. -- Is there enough evidence to prove Loyd Groves killed his former mistress almost 30 years ago? That's what a jury of 12 will be discussing as closing arguments are wrapping up in Lock Haven.
Kathy Heckel's family walked into the Clinton County Courthouse prepared to listen to closing arguments in the case of their loved one who has been missing since 1991.
Loyd Groves, 69, from Beaver County, is on trial, charged with both first-degree and third-degree murder.
Investigators say Groves and Heckel worked together and were having an affair.
The prosecution believes when Heckel tried to break it off, Groves got jealous, killed her, and got rid of her body.
During closing arguments, Grove's defense team told the jury the prosecution's case is just a theory, and that much of the prosecution's information comes from one source: a man who should have been treated like a suspect and was also having an affair with Heckel.
The defense claims a timeline shows Groves would have had 10 minutes to kill Heckel and dispose of the evidence the day Heckel went missing.
In court they said, "what (the prosecution) outlined defies logic. If it ever occurred the way they are speculating it occurred, it's just not possible."
Earlier this week, the prosecution revealed a speck of Heckel's blood was found in Groves' vehicle.
The defense said less than a month before she went missing, Heckel needed medical attention after she cut her finger, and that she often rode in that van.
In their closing arguments, the prosecution called Groves the planning man, calling evidence including duct tape, running shoes, knives, and a gun a kit made to murder.
The deputy attorney general says, "the evidence shows that only one man had the opportunity, the means, and the motive."
If he's found guilty, Groves could be facing years in prison.