Her murderer, a Nigerian migrant drug dealer named Innocent Oseghale, was convicted and sentenced to life in prison with 18 months of isolation in May 2019.

In the park, Mastropietro was believed to have been led to a 29-year-old Nigerian named Innocent Oseghale, who had arrived in Italy on 26 August 2014, during a peak migration period.

[8] Soon after, Italian police said they found her bloodied clothing at the home of Innocent Oseghale, a Nigerian who moved to Italy in 2014 but who had dropped out of a refugee assistance program and begun selling drugs.

Flowers were left by the local Nigerian community and diplomatic staff, Rome mayor Virginia Raggi, and Luca Traini, who opened fire against several African migrants in Macerata days after the murder.

[18] In June 2020, Mastropietro's uncle and lawyer Marco Verni took the knee in her memory during court proceedings during the George Floyd protests.

[21] In October 2020, 22-year-old Romanian Claudiu Nitu, Mastropietro's ex-boyfriend, was sentenced to three years in prison for attempting to introduce her to prostitution in order to pay for drugs.

[22] In January 2023, Mastropietro's mother, Alessandra Verni, wore a t-shirt with images of her daughter's decapitated and dismembered body as a protest to a hearing where Oseghale was contesting some additional charges related to the murder.