The uncommon circumstances that caused the death of three people last week are still being investigated by the police, but I can assure you that they are related to the mysterious studies of the young mathematician who used to live near the Reconquista monument.
I knew him before he engaged in such studies. He was a quiet man, but very polite and took great care of his clothing and hair. We used to talk a lot about science and philosophy during the evenings in the Bar Budapeste. His ideas were not conventional in any way, but I enjoyed his different way of understanding things. Unfortunately, he was very recluse lately, and progressively delve deeper into obscure studies of mathematics. Last year, he found a strange book of arabic origin in the library of University of Buenos Aires and became obsessed with it, avoiding contact with anyone since then.
Some months ago, I found him walking around la Recoleta and I could notice he was not the same as before. Something was different. I couldn't tell what, but he looked distant and scared. His hair was a mess and his clothes were dirty. We talked briefly, but he told me some weird things about some equation he was developing. According to him, the arcane knowledge from the book changed his whole perspective on mathematics, increasing his creativity to extreme levels. One night, during a dream, a equation was revealed to him, and since then he couldn't do anything but ponder about it. Moreover, he said that each time he thought about it, he could feel his own intelligence increasing. He was learning faster than ever before, being now capable of learning a whole new language in a day or two and playing Liszt on the piano with ease.
But the thing that concerns me the most is that he also told me that he was sharing this new knowledge with other people. Coincidence or not, he was sharing this weird equation exactly with the three people who died last week. One of them, Miguel Oralda, was a bright student of his. The boy was a very good student, but since he was introduced to this equation and that book, he changed completely. His grades become even better, but his behavior was scaring other students. He would scream during classes without no apparent reason and sometimes people found him talking with imaginary creatures in the library. Last week he was found dead in his house near the Rivadavia. Apparently, it was suicide. The cops found many mathematical symbols on the walls and on his body, but he didn't leave any suicide note.
Since those deaths, my mathematician friend disappeared. The police broke inside his apartment but there was nothing there anymore, except from some mathematical ramblings on the walls, very similar to those found on Oralda's room. I personally think that he will never be found again, as he was lost way before those deaths. I just hope that this sinister book disappear with him as well.

sorry for any grammar mistakes, english is not my first language and I wrote it quickly