"As I was sure of, just like my daughter Brittany, there was no kind of drug overdose [for Simon Monjack]," Sharon Murphy said in a statement Wednesday.
The Los Angeles County Coroner found that the May 23 death of Monjack, 40, was caused by acute pneumonia and severe anemia – the same two causes of Murphy's death five months earlier, CNN reports.
"I am calling on the media to stop the reckless innuendos, that my daughter and son-in-law misused any kind of prescription medications," adds Sharon, who previously told PEOPLE her daughter never abused drugs.
Though she is "still in shock and mourning" over Murphy's and Monjack's deaths, Sharon thanks fans for their prayers. "I am getting stronger every day," she says.