EXCLUSIVE: Kelsey Grammer's Darkest Secrets Resurface as He Grieves 'Cheers' Co-Star George Wendt — Including Sister's Murder and Abortion Nightmare

Kelsey Grammer may be best known for playing the sensible psychiatrist Frasier Crane on Cheers and spin-off, Frasier, but off-camera his personal life has been a roller coaster.

RadarOnline.com can reveal the shocking bombshells the actor included in his memoir, Karen: A Brother Remembers.

On May 6, Grammer's highly anticipated new memoir unfolded the most devastating personal tragedies that shaped the actor's life, including the death of his sister, Karen Grammer.

Kelsey said of his sister's killer: "It is ammunition to keep Freddie Glenn in jail."

Freddie and his late accomplice, Michael Corbett, murdered Karen and four others in Colorado Springs in 1975. The convicted murderers initially planned to rob Red Lobster — a restaurant where Kelsey's sister was working — but demanded she go with them instead.

They ultimately took Karen into their car, tied her up and took her to an apartment, where they repeatedly raped her. After assaulting the victim, they drove her to an alley and subsequently killed her.

According to Kelsy, Freddie "almost decapitated" Karen after stabbing her 42 times.

Kelsey recalled, "The coroner noted that through a gaping wound in her neck, he could see all the way into Karen’s lung. … There were defensive wounds on her hands," noting his sister crawled "400 feet from the place where she had been stabbed" to ask for help.

The Cheers alum continued: "Bloody fingerprints mark the trail of her final moments at exactly 3'6" along the office and walls of the trailer park. She had been on her knees, crawling her way. Seeking help with her last ounce of life… She had fallen backward from the trailer door after knocking for help. It was her last hope and disappointment."

Kelsey identified Karen's body one week after he reported her missing.

"The murder killed a corner of my heart," he wrote in his memoir, in which he called his sister "love of my life" several times.

Kelsey added, "(Karen) an Oreo cookie dipped in an ice-cold Coca-Cola. She was a poem, a light, fun, innocent, and wise."

In 1976, Freddie was sentenced to life in prison for the killings. He has been slapped with four parole denials before his next hearing in 2027.

Following Karen's murder, Kelsey found himself struggling with addiction as he tried to cope with his family's traumatic history.

He reflected in his book: "I cursed myself with too much drinking and drug abuse. And some fairly exotic sexual behavior. Started out being a lot of fun and then the fun ran out.

"It was my way of burying myself along with Karen, until the only option was to deal with it and live my life. To mourn my sister without destroying myself."

Kelsy also wrote: "To resolve grief does not end it. Resolving it is a balancing act. Living with grief while not undermining life. To abide with it. Not surrender to it. It did almost kill me."

Sharing how he survived, Kelsey confessed he just "would not quit," as he did not want "to let Karen down." Although he turned to substances in the years after losing his sister, he soon realized he must keep living.

The actor shared: "I had a foundational belief: I am obligated to fulfill the life I was given. Anything less would have been an affront to my family and to God. They gave me life. I owed it to them and to myself not to quit. Owed it to Karen. And to God."

In Karen: A Brother Remembers, Kelsey revealed two women in his life experienced abortions — including his wife, Kayte Walsh.

He wrote: "I know that many people do not have a problem with abortion, and though I have supported it in the past, it eats away at my soul."

According to Kelsey, Kayte had an abortion when she was 13 weeks pregnant with twins after the male fetus' sac ruptured and did not repair itself.

The Cheers alum explained: "Doctors advised us his continued growth without the safety of his amniotic fluid would surely kill him and probably take Faith too.

"We killed our son so Faith might live. We wept as we watched his heart stop. It is the greatest pain I have ever known. Kayte's scream was enough to make a man mourn a lifetime."

Decades before Kayte got an abortion, Kelsey faced a similar situation when his girlfriend became pregnant in 1974 but did not want to keep the baby despite pleading with her "to save our son's life."

He confessed: "I supported the idea that a woman has the right to do what she wants with her own body. I still do. But it's hard for me. Still is."

Six months before Karen died, he reportedly "volunteered" to have his son's body "vacuumed out of his mother's."

The Frasier star admitted: "I regret it. That's all I meant to say."

Kelsey went on to call out his unnamed girlfriend's physicians, saying: "The doctor, or so-called doctors, who have executed generations of children in this manner — I have no idea how they call themselves doctors. Something about the 'first, do no harm' thing. But I offer no controversy."

Elsewhere in Karen: A Brother Remembers, Kelsey recalled reconnecting with Karen Lorre decades after they worked together in a 1988 episode of Cheers.

He wrote: "We had dinner the other night with a lovely woman. Karen.

"We had met before on Cheers and were meeting again through a mutual friend, Bill. It had the ring of something more important than just happenstance. Karen."

The Swing Vote actor said he had a poignant moment with the 63-year-old model after he told her he would be writing about his sister, who was his one-time costar's namesake.

He added: "She registered a kind of surprise. It was fun to reminisce with her. Just a coincidence but I will send her a copy of this [book] one day. She has become a friend and I am happy to welcome her to the world of my sister. Kayte and she have become friends. Always nice to welcome another Karen into my life."