Ivaylo Popov, 43, a man of Bulgarian descent, was killed in a mass shooting at his Chicago apartment on October 12, 2019. He, his wife Tsvetanka Kostadinova, 43, and his mother Iskra Pourel-Popova, 65, were among five people fatally shot after the family finished dinner and a neighbor, 66-year-old Krysztof Marek, entered their unit and opened fire. The attack also killed David Hanik, 61, and Jolanta Topolska, 53.

Court filings say Marek had left threatening notes in his apartment before the attack, including messages such as No mercy and They have to pay for it, and had been facing eviction over unpaid mortgage and fees. After the shooting he surrendered to police and was charged with five counts of first-degree murder and denied bail. Memorial services were held for the victims and the family expressed gratitude for community support.

What details about Ivaylo or the other victims’ lives or about the building might help explain how this escalated so quickly?