ST. CLAIR SHORES, Mich. -

What happened to Ramsay Scrivo?

Investigators say his mother, Donna Scrivo, dismembered his body but it's not yet clear how the 32-year-old St. Clair Shores man died.

Story: Mom charged with dismembering adult son's body

However, now the Local 4 Defenders are learning new information about how Ramsay may have died. Documents show why the toxicology report is key.

In the months before his death, Ramsay Scrivo revealed he feared someone was trying to poison him.

Sources close to this investigation say there are no visible gunshot wounds on the remains collected and it is believed the person responsible for this murder may have strangled Ramsay Scrivo to death.

"When somebody's strangled, almost always it's by somebody that they knew. So in this particular case you have a mother and son. I've got to believe that's going to show up on here. You don't have too many strangers walking up and strangling somebody for the manner of death," said Tom Berry, a former Detroit police detective.

Death by strangulation is right now a major focus in the case, but other possibilities can't be ruled out, which is why the toxicology report is key.

In the petition for guardianship filed last year by Donna Scrivo, she revealed her son was taking several prescription medications including Xanax. She also revealed he was suicidal and she told those evaluating her son that he believed a friend of the family was trying to poison him. The medical examiner is waiting for all the pieces of this complicated puzzle to come together.

"Those toxicology reports are going to show was he drugged? Was he on something? Did she numb him up? Did she knock him out? Or did she not?" said Berry.

Donna Scrivo remains locked up and on suicide watch at the Macomb County Jail. She is not cooperating with the investigation.