A court in Madrid on Monday launched an investigation into alleged insults and threats made against several politicians and journalists, including the Spanish capital's mayor, in a group chat composed of over 100 local police officers.

Municipal sources confirmed to EFE that a court was investigating the information published in an exclusive by online daily eldiario.es, which gained access to leaked conversations on the popular messaging app WhatsApp that appeared to show police officers making death threats and directing vitriol at progressive politicians such as Madrid Mayor Manuela Carmena, their boss.

"Let that old bitch die already," read one of the messages. "Despicable hag," said another about the 73-year-old mayor, who assumed office in June 2015.

"It's terrible that she wasn't at the Atocha office when they killed her colleagues," a message said in reference to Carmena, a co-founder of a labor law firm that was targeted by far-right terrorists who murdered five lawyers and injured four in the 1977 Atocha Massacre.

Around 115 armed municipal agents doing the night shift patrols in Madrid participated in the chat, although only half a dozen of them were very active and wrote most of the insults and threats, according to eldiario.es.

The scandal was uncovered when a member of the chat and union representative decided to file a police complaint last week over hate crimes and threats.

The whistleblower alleged he had received death threats after he rebuked his colleagues for misusing a chat that was ostensibly created to discuss labor issues and instead was being filled with politically-motivated invective.

Madrid's city hall has subsequently offered him a police escort.

Journalists were also the target of gruesome death wishes: following the Aug. 17 terror attack in Barcelona, one of the members said he wished that prominent newscasters Ana Pastor and Antonio García Ferreras, who work at La Sexta television network, would become victims in the next terror attack.

"I hope La Sexta blows up with them inside," the message said, adding that Pablo Iglesias (leader of the left-wing party Podemos) and Gabriel Rufián (spokesman for Catalan pro-independence party Republican Left of Catalonia) should also be inside the building when it exploded.

The message's author added that he wanted them to die "a slow and agonizing death."

Several politicians reacted to the news by condemning the messages and calling for a thorough investigation into the alleged offenses.

"This is intolerable and must doubtlessly be investigated," tweeted Pedro Sánchez, the secretary-general of the Socialist Party (PSOE). "Manuela Carmena has all my support and that of my party."

Alberto Garzón, leader of the United Left party, said his organization condemned and despised the threats against Carmena.

The Madrid court's investigating magistrate has contacted the city hall with the aim of identifying the messages' authors and summoning them to testify under oath, municipal sources confirmed.