Comedian Patton Oswalt celebrates the achievement of his late wife and author, Michelle McNamara, as her book, I'll Be Gone in the Dark tops the New York Times Best Selling list.

In April 2016, McNamara died in her sleep at the age of 46. She left a husband, an 8-year-old daughter, and an unfinished crime book which she started researching years before her passing.

On a Twitter post on Wednesday, Oswalt attached a snapshot bearing the list of New York Times Best Selling books for 2017 including McNamara's in the number one spot in the non-fiction category.

"I hope you know, sweetie. I feel like you know. And I hope you know it when your work leads to his capture. #IllBeGoneInTheDark debuts at #1 on the @nytimes bestseller list. I'm so proud of you," wrote Oswalt.

Following the death of his wife, the 49-year-old actor and voice talent also commemorated McNamara's written work by posting a picture of her tombstone with the book sitting on top of it.

In a tweet dated Feb. 27, Oswalt congratulated his late wife for doing a good job, adding that her writing was brilliant. He also took notice how McNamara brought "kindness to chaos" in writing about the crimes and the victims and their families' fate.

The Manhunt

I'll Be Gone in the Dark features McNamara's thrilling account on her investigation on the so-called Golden State Killer, who has a record of 50 cases of sexual abuse and several murders in a decade period from 1976.

Although McNamara was unable to finish her book, Oswalt salvaged it by writing an afterword. Other contributing writers also helped complete the book through her years of extensive research.

In an interview with Entertainment Weekly, Oswalt described her late wife as a logical person who has a lot of compassion. The actor said that McNamara would immediately come to the rescue of a person who becomes a victim of any cruelty because that is her logic seeking for truth and justice.

Oswalt also explained that McNamara's motivation in writing the book was the pain of the survivors and the family members that have lost their loved ones due to the Golden State Killer.

Newfound Love

Eighteen months after McNamara's passing, Oswalt got married to Meredith Salenger in November 2017. They were joined by closely-knit friends and family members at the Jim Henson Studios in Los Angeles.

Salenger, 47, is an American actress who is known for her role in The Journey of the Natty Gann (1985) and Dream a Little Dream (1989).

Tags: New York Times Best Selling I'll Be Gone in the Dark Patton Oswalt Michelle McNamara Meredith Salenger