Ryan Synder, the biological father of the victim, barricaded himself inside his home at 57738 Pendleton Drive in Elkhart County with his two children Saturday night after deputies arrived at the house to perform a welfare check at 9:30 p.m. 

According to court documents, a woman called authorities saying she was out of state but wanted deputies to check on the two children she shared with Snyder who were currently in his custody. She said she received a disturbing video call from one of the children who was crying. 

The woman told authorities she could hear her four-year-old crying while Snyder was in the background repeatedly saying he was going to "end it all."  She did not hear or see her two-year-old child during the call. 

When no one answered the door at Snyder's home, police began looking in windows when they saw an AR-15 style rifle with a drum magazine sitting on the kitchen table.

That is when the 18-hour standoff began, with the SWAT team was officially being called in at 10:58 p.m. Saturday night.

The mother says she dropped the kids off with Snyder around 7 p.m. on Friday, July 5 and that they were both in good health. 

"She states that Snyder was unusually and uncharacteristically pleasant during this interaction," court documents state. "[She] advised that over the last three weeks Snyder has been manic saying things like ... 'God is going to have his vengeance' and that he was carrying out 'God's will.' She stated that she first thought Ryan was talking about their custody situation, but then realized that he was planning on killing the children."

She told authorities she received another video call around 8:30 p.m. on Sunday, July 7 where Snyder threatened the children and used them to emotionally manipulate her.

Authorities say Snyder did not answer when they attempted to call his cell phone and did not respond to commands being given over the public address system.

"On several occasions while on scene, police were able to see Snyder wearing body armor and carrying rifle. Furthermore, gunfire could be heard coming from within the residence at times," authorities said. 

After calling in the Indiana State SWAT team, entrance was made into the house at 3:34 p.m. 

The two-year-old boy was found dead in a basement bedroom and their older sibling was found hiding, but alive.

A forensic autopsy was done at the Homer Stryker School of Medicine at Western Michigan University on Monday. The results of that autopsy are pending further analysis and testing and will not be confirmed for several weeks.

"Accordingly, cause of death has not yet been officially determined," authorities said.

Snyder is currently being held with no bond.