The wife and son of Argentine Sen. Luis Naidenoff, the head of the governing Cambiemos coalition in the upper chamber, were found dead on Monday in their home in the northern city of Formosa, official media reported.
The cause of death is still under investigation, the assistant chief of the provincial police told the state-run Telam news agency, but authorities believe the most probable scenario is that they died from carbon monoxide poisoning.
Naidenoff was married to Cinthya Sonaridio, with whom he had a daughter and a son.
Lawmakers did not delay in sending their condolences to Naidenoff via the social media, as did Argentine Vice President Gabriella Michetti, who also heads the Senate.
"My very best wishes to Luis Naidenoff at such a tragic time, all my affection and support," wrote the president of the Senate on her official Twitter account.
Similar sentiments were expressed by governing party legislator Graciela Ocaña, as well as by opposition lawmaker Maria Laura Rodriguez.
"Sad news. My most heartfelt condolences to Senator Luis Naidenoff, best wishes," wrote Ocaña.