This strange story took place in 1977 and is truly extraordinary. February 25, Moscow, Domodedovo airport. A report was received from one of the airliners about the death of a person on board and a request for an unscheduled landing. Permission was granted and soon the aircraft landed. Airfield services and medics rushed to it. To their surprise, a young stewardess had died. The doctors examined the deceased and asked to call the police - the girl had obvious signs of cyanide poisoning. The investigative-operative group that arrived confirmed the conclusions of the doctors. But who could have poisoned the stewardess at an altitude of 10,000 meters? Or maybe she herself decided to say goodbye to life? Law enforcers had to figure it out.

The flight attendant's name was Alla Korsakova and she was only 22 years old. Soon pathologists sent a report saying that she was pregnant at a small term. And also the examination showed that the girl had taken the poison along with the tea. Which means someone deliberately took Alla's life. The investigators questioned all members of the crew of the airplane and tried to restore the events of the fateful flight. The flight was in normal mode, there were few passengers and Alla Korsakova brought tea in the cockpit. Drinking it four - Alla herself, aircraft commander Volchkov, co-pilot Knyshev and flight mechanic Koltsov. It was Koltsov who first came under suspicion, as he had a romantic connection with Alla. Nikita Koltsov was famous for the fact that his relationship lasted a short time and as soon as he found a new girlfriend, the old one was no longer needed. So maybe he was afraid of responsibility, having learned about the pregnancy of his girlfriend and decided to get rid of her? That theory made sense.

During the inspection of Korsakova's apartment, the investigators' attention was drawn to a tear-off calendar hanging in the kitchen. The torn sheets ended on the date of February 25, which was the day the young stewardess died. On the calendar sheet, a short phrase was written in uneven handwriting: “Watch out for K.” The detectives wondered. Who was this K? The flight engineer Koltsov? Or co-pilot Knyshev? Or maybe it was about the aircraft commander himself? Which of them had made Alla write the warning to herself? But no evidence on all three could not be found, and the motive was as if only Koltsov. So the detectives focused their attention on him. But they were wrong, he was not the culprit. This became obvious when, a few days later, the body of Koltsov himself was found in his own apartment. The cause of death was asphyxiation. The impression was that someone was purposely eliminating crew members. But who? There were two suspects - the commander and the co-pilot.

We talked to the commander Volchkov. He said that he treated Alla in a fatherly way, tried to protect her, but Koltsov disliked him, because he had turned Alla's head and it was clear how it would end. And in general, the flight mechanic was windy and narcissistic. Volchkov assured that he had nothing to do with the death of both, but the co-pilot Knyshev, in his opinion, is also not to blame. They say Knyshev is going through a divorce and is completely absorbed in family squabbles. The flight mechanic and stewardess were uninteresting to him. With Andrei Knyshev personally could not talk - he just asked for a vacation and went to Yaroslavl to his ex-wife and son. However, the Moscow detectives asked their colleagues from Yaroslavl to talk to him. When the Yaroslavl law enforcers approached the house where Knyshev's ex-wife lived, a man with traces of blood on his hands jumped out of the entrance. He himself ran up to the policemen and, panting with excitement, explained that his wife had been attacked and asked to come with him.

It turned out that the attack was committed on Oksana Knysheva, the ex-wife of Andrei Knyshev, and it was he who ran out to meet the policemen. The woman was taken to hospital in a serious condition, but Knyshev had a serious conversation with the pilot. He told the law enforcers that an unknown person tried to rob his ex-wife's apartment. Seeing that the landlady was in the apartment, the criminal took out a knife and attacked her. At that moment Knyshev himself entered the apartment and scared the criminal away. The policemen listened to the pilot, but did not believe him. Having questioned the old ladies at the entrance, they already knew that they had not seen any criminal running out, but had only seen Knyshev entering the entrance. During the inspection of the apartment, the law enforcers' attention was drawn to the ventilation grate in the kitchen, which was loose against the wall. It took a lot of work, but as a result, a kitchen knife was extracted from the ventilation shaft. All that remained was to check the fingerprints on the handle.

An expert examination showed that the fingerprints belonged to Andrei Knyshev. He was detained. At the interrogation he did not deny it and told all his strange story. His wife Oksana was a beauty and Knyshev was insanely jealous of her from the first day of acquaintance. Over time, this mania began to worsen, he constantly suspected his wife of betrayal, demanded a report almost every step she took and even followed her. These suspicions he spoiled the life and himself and his family. When their son Igor grew up, Knyshev suddenly seemed that the child is not from him. He fixated on this thought and now tormented his wife with constant questions, who is the real father of Igor. Oksana guffawed, not realizing that her husband was on the verge. Once Knyshev saw how at the airport Oksana communicates with flight engineer Nikita Koltsov. They were joking and laughing and he suddenly realized who Igor's real father was. It's Koltsov!

The thought burned him. He began to distance himself from his son and wife, bringing the situation to divorce. And at work he constantly saw the hated Koltsov and dreamed of one thing - to get rid of him, because he broke his life, Knyshev! He was even more angry when he learned that Koltsov had an affair with a young stewardess Korsakova. He tried to talk and warn Alla not to get involved with this bad man, but Alla was more frightened than Knyshev himself, so he wrote a warning to himself on the calendar: “Be careful with K”. And Knyshev finally decided to eliminate his enemy. HE managed to get cyanide and slipped it into a cup of tea Koltsov, but this cup took and drank Alla Korsakova. She died by accident! But this did not stop Knyshev in his desire to take revenge on Koltsov, and a few days later he came to the flight mechanic's house and killed him, no longer particularly secretive.

But he was not satisfied with that. He had to take revenge on his wife, who had betrayed him. He took a vacation and went to his family under the pretext of improving relations. He attacked Oksana, but through the window he saw the policemen arriving and hastily made up a lie about the robbery and ran towards them. This saved Oksana...

Andrei Knyshev was sentenced to capital punishment. He made up some kind of betrayal, lost his loving family, ruined the lives of two innocent people and eventually lost his own. But Oksana was faithful to him....