The body of who is believed to be a woman who went missing in Butler County over the weekend was found in New Castle Monday night. 

Police say around 7 p.m. a man called Neshannock Township Police to investigate what he thought were human remains he had found on his property.

Pennsylvania State Police in New Castle took over the investigation and say there is evidence to believe remains belong to 26-year-old Melissa Barto, although Troopers say they are still waiting on an official autopsy to confirm the identity. 

Police say Barto's family first reported her missing Friday, June 9 when she didn't show up for her six-year-old daughter's kindergarten graduation ceremony. 

Police believe Barto was shot and killed by her 21-year-old boyfriend, Ishemer Ramsey, in his car following an altercation the previous evening, June 8.

Her body was then hidden at another location which police are working to identify, officials say. 

Ramsey was arrested over the weekend and charged with homicide. Now, officers have arrested a second suspect in connection with the homicide. 

"Hopefully we can give the family some closure," said Eric Hermick, Crime Section Commander for the Pennsylvania State Police Major Case Team. "They can have their daughter back, the mother of the six-year-old back, and we can move forward with our prosecution."

Police say they believe the suspects left Barto's body to solicit "some materials" before they returned and moved her body to where it was eventually discovered on Old Pulaski Road in New Castle. 

Ramsey is believed to have military experience as a United States Marine Reserve. 

"By all accounts, this victim was a respectable young woman, and the guy that killed her is a monster," Hermick said.

Hermick would not further comment on the condition of the body out of respect for the victim's family, saying it was too horrific to talk about. 

Police say they do not know Ramsey's motive for allegedly shooting and killing Barto, but they did say the couple had a tumultuous relationship. 

Stay with 21 News for more on this developing story.