Patton Oswalt reveals wife Michelle McNamara's cause of death

This article originally appeared on PEOPLE.com.

Patton Oswalt has revealed his wife Michelle McNamara’s cause of death, nearly one year since she died unexpectedly in her sleep at age 46.

“We learned today the combination of drugs in Michelle’s system, along with a condition we were unaware of, proved lethal,” the actor and comedian wrote in a statement to the Associated Press on Friday.

Oswalt also explained that the couple, who wed in 2005, had “no idea” she had a condition that caused blockages in her arteries.

The blockages, combined with her taking the medications Adderall, Xanax and the pain medication fentanyl, caused the mother of one’s death in April 2016, Oswalt said.

McNamara’s cause of death remains listed as pending, Los Angeles coroner’s Lt. David Smith confirmed to AP.

In an October interview with The New York Times, Oswalt recounted the last night he had with his wife, speculating that she may have accidentally overdosed.

McNamara, who was writing a book about a serial rapist and killer at the time, was working long days and nights and was unable to sleep due to anxiety and nightmares that kept her up at night.

So worried about her health, Oswalt suggested she take a night to “sleep until you wake up.” On April 21, McNamara took some Xanax and went to sleep, but never woke up.

The next morning, Oswalt remembered waking up early to get their 7-year-old daughter Alice dressed, packed and off to school. On the way home, he picked up an Americano coffee and left it on McNamara’s bedside table — around 9:40 a.m., he recalled.

Hours later, he checked to see if his wife was up yet. She was still in bed — not breathing. The paramedics pronounced her dead at the scene. While a cause of death was not declared by the coroner’s office at the time, Oswalt said he believed the Xanax was to blame.

In December, the father of one penned an emotional essay for GQ about his first year as a single parent.

“This is my first time being a single father. I’ve missed forms for school. I’ve forgotten to stock the fridge with food she likes. I’ve run out of socks for her. I’ve run out of socks for me. It sucked and it was a hassle every time, but the world kept turning. I said, ‘Whoops, my bad,’ and fixed it and kept stumbling forward,” Oswalt wrote.

“I’m going to keep going forward, looking stupid and clumsy and inexperienced at first, then eventually getting it, until the next jolt comes, and the next floor drops out from under me, until there are no more floors.”