In 1920, the year after Tausk's death, in his essay Beyond the Pleasure Principle. Freud introduced the concept of the “death drive.”

July 2, 1919. The day before Tausk's death

According to Roazen, By the early morning hours of Thursday (July 3, 1919) Tausk had determined to kill himself. (1)
But Roazen couldn’t have known when Tausk decided to kill himself, let alone when died. Most probably, this information about the timing of Tausk’s death originated in the Tausk’s obituary written by Freud. And since it was Freud who specified the time of Tausk’s death, there’s a valid question: how could Freud have known when Tausk died, unless he was present on the occasion? In fact, since apparently he was alone all night, Tausk’s death could have taken place any time on Wednesday night, after his return from his fiancé’s performance, or at any time on Thursday night.

Itemization?

Allegedly, while preparing for the suicide, Tausk, wrote a will with a lengthy itemization of all his possessions, noting down even the smallest details … He also wrote and sealed two letters and left them on his desk—one to Hilde [Tausk’s fiancé], the other to Freud. (2)
Remarkably, what happened to the will wasn't revealed. Apparently, unless the two letters, it wasn't left on the desk, so where was it? Notably, unlike the absence note, and the letter, to Freud, the will doesn’t seem to have been preserved, which poses a valid question. Having no access to the will, Roazen couldn't have known that the will contained a list of Tausk’s of, ALL his possessions … to the smallest details. This is yet another example of Roazen acting as a fiction writer rather than a factual biographer.

Suicide letters

Remarkably, Roazen wasn’t surprised that Tausk - shortly before his death - instead of writing farewell letters to his sons and their mother, his ex-wife, his parents, and friends - rather wrote an homage to his sworn enemy, Freud.
But, what if it wasn’t Tausk, but his murderer, who wrote those letters? Notably, besides the letter to Freud, there was only a letter to Tausk's fiancé.
Could it be that the murderer - assuming that Tausk was murdered - decided to write a farewell letter only to Taus's fifiancé, the one person, who wasn't very familiar with Tausk’s handwriting? In fact, Tausk met Hilde only, after his analysis was interrupted (3), thus, only three months before his death. And since they both lived in Vienna, it is unlikely they exchanged lots of written messages.

Sipped Slivovitz?

According to Roazen, While completing this writing he [Tausk} sipped Slivovitz, the Yugoslav national drink. (4) Where this information came from Roazen didn’t reveal. Thus, this is only Roazen's conjecture. After all he wasn't there, and thus he couldn’t know whether Tausk was drinking before, after, or while writing the letters, or at all. And if Tausk was indeed drinking, there's a question of whether he was drinking alone, or sharing the drink with his visitor, or visitors, who overwhelmed and killed him in the morning, as Freud stated?

July 3, 1919. The day of Tausk's death

This is how Roazen described Tausk's death: he tied a curtain cord around his neck, put his army pistol to his right temple, and pulled the trigger. ... Besides blowing off part of his head, as he fell, he strangled himself. (4)
This is yet another example of Roazen’s speculative habit. As a matter of course, since Roazen wasn’t present during Tausk’s suicide, he couldn’t have known what really happened, and in which order.
In fact, this could have been yet another case of a staged suicide. And most of them have never been uncovered. Keeping in mind how primitive police work was during Tausk’s lifetime, his murder, assuming it was a murder, could have been easily misclassified as a suicide.
And the way the suicide, or murder was performed, shows that it wasn’t planned. Wouldn’t a man, that intends to commit a suicide by hanging, prepare himself by buying a proper rope for hanging? Who knows whether a curtain cord might be strong enough to carry a weight of a man? And if this was a suicide committed at the spur of the moment, since the gun shot would suffice, why also hang oneself?
Moreover, tying the curtain cord around one’s neck is not enough to kill oneself. The cord needs to be attached somewhere. Oddly, the question of where the cord was attached is not asked. Were there bars in the windows? A lamp hook in the ceiling wouldn't be able to hold the weight of a man.
The whole uniquely bizarre scene of Tausk’s death reminds one of the expression, “the last curtain”, describing ending of something that lasted a (too) long time. Again, which needs to be pointed out, the detailed description of how Tausk died is only a figment of Roazen's imagination. All we can tell for sure is that Tausk was found hanging and shot in the head.
Considering the oddity of Tausk’s suicide, and its visibly staged character, there are a couple of alternatives, and more logical, explanations of what happened. A visitor, or visitors, came early in the morning. While he/they were drinking Slivovitz together with Tausk, one of the visitors shot Tausk, and then he/they hanged him. Alternately, since Tausk was much larger than Freud, (5) assuming Freud killed him, Freud would have needed to somehow gain the upper hand over his adversary before being able to "neutralise" him.
Thus, another possibility is that Tausk was somehow immobilised, possibly by an unexpected blow to the head, or by likewise unexpected injection of a paralytic drug, like succinylcholine, to which Freud, as a doctor, had easy access.
Then, one of the visitors shot Tausk, and then he/they hanged him. Assuming it was a murder staged as a suicide, the fact that a curtain rope had been used indicates that the hanging of the victim wasn't part of the original plan. (In many cases, the killer improvises, when staging the murder scene, using the paraphernalia available at the place of murder.)
Then the perpetrator, possibly with assistance from his partner, wrote the will, and the two suicide letters, and left. Alternatively having planned the staged murder, he/they may have brought the will, and the letters, written in advance, with him/them.
Tausk, Freud's main competitor, was no more. As a matter of course, the visitor or visitors, assuming his, or their, presence, since Tausk let him or them in at his late hour, would have been someone Tausk knew well. Was this mysterious visitor, Freud, assisted by someone; why not by his favourite daughter, Anna? Murder was constantly on Anna’s mind, even appearing in her dreams. Could she have been dreaming, among others, about having witnessed Tausk’s staged “suicide”?
(1) Roazen, Paul, Brother Animal: The Story of Freud and Tausk, (1969, p. 125).
(2) Roazen, (1969, p. 125).
(3) Roazen, (1969, p. 110).
(4) Roazen, (1969, p. 125).
(5) Roazen, (1969, p. 165).

Roazen must have been delusional, when writing the story of Tausk and Freud, since he bizarrely claimed that,
By killing himself he [Tausk] could be reconciled with Freud as well as confirm his own guilt. On the one hand he could be rid of Freud’s teachings only in that way; having identified with Freud so much, Tausk could slay him by suicide. On the other hand, by refusing the “easy” alternative of going off and founding his own school, Tausk could match his master’s integrity.
What's so wrong with all those people writing about psychoanalysis?
Roazen, Paul, Brother Animal: The Story of Freud and Tausk, (1969, p. 133).

Tausk's castration

Remarkably, Roazen believed that, It was no accident that legend has it that Tausk castrated himself. (1) Oddly, how is it that already this fact doesn’t ring the alarm bells for Roazen? Is it even believable that anyone would perform this kind of operation on oneself, before committing a suicide? What would be the point of such a meaningless suffering? In fact, if the castration did happen, it is much more believable that the castration was performed by Tausk’s murderer. Besides finding out who the murderer was, the only question remaining is it whether it was performed before, or after, Tausk’s death,
In My sister, my spouse; a biography of Lou Andreas-Salomé of (1974), without mentioning the source, its author, Heinz Peters, claimed that, a week before his marriage despair overwhelmed him [Tausk] and he killed himself. Rumor has it that he died a particularly gruesome death by first castrating himself. (2) (This quote, is the source of Roazen’s claim about Tausk’s self-mutilation.)
Remarkably, hinting at Freud's involvement, Roazen claimed that, Freud’s male pupils wanted his love, but he gave it only if they came close to castrating themselves as creative individuals. (3) And if they didn’t, neither intellectually, nor otherwise, apparently Freud was happy to oblige.
Apparently, the double suicide was allegedly accompanied by an even more, bizarre, third event, thus becoming a triple suicide. But, if castration did occur, the claim that Tausk committed suicide becomes even more suspicious.
After all, what would be the point of mutilating oneself, suffering senselessly, before one’s imminent demise? In fact, the whole death scene is more and more looking like a theatrical, ritualised, staged murder executed by a jealous competitor. As a matter of fact, a castration intimates a sexual motive of jealousy and revenge intended, according to Freud, as a punishment for incestuous wishes toward the mother and murderous fantasies against the rival father. How about Tausk's castration being the consequence of Freud's jealousy and revenge towards his sexual and psycho-analytical competitor?
As, Freud claimed in The Case of Little Hans (1909), the son fears that his penis will be cut off by the father because he desires his mother. Applying this Freudian claim in the context of his relation to Tausk and Lou - Freud acting as a father, Tausk as a son, and Lou, eighteen years older than Tausk, playing the mother – it is Tausk, the son, that would have been emasculated by Freud, the father. In fact, jealousy played a large part in the triangular relationship of Freud, Lou and Tausk since, even though Freud courted Lou, it was Tausk, not Freud, that Lou chose for a lover. And, Freud lived as he preached.
Assuming that Tausk was murdered, already the fact that he was castrated by his murderer is an obvious clue that it was the murderous father of the horde (4) that was behind both the castration and the murder. A point in case, as Anna Freud's biographer pointed out, an author openly stated that Freud wanted his pupils to be castrated. (5) And, at least one of them, if we are to believe the rumour, was castrated, presumably before his death.

Freud … strict in the demands he made of his pupils; he permitted no deviation from his orthodox teaching. … If we do consider him as a founder of a religion, we may think of him as a Moses full of wrath and unmoved by prayers. *
* Graf, Max, Reminiscences of Prof. Sigmund Freud, Psychoanalytic Quarterly, 11.4. 1942, pp. 465-76., p. 471.

One day, ... Moses... seeing no one ... killed the Egyptian **
** Exodus 2:11

Continues with Part 4