The trawling of a genealogical website for a familial genetic match of a suspect seems to be inspired by the Golden State Killer out of California.
The Golden State Killer, on whom Infinity is loosely based, was a nickname coined by journalist and true-crime author Michelle McNamara, who, until her death in 2016, was married to actor/comedian Patton Oswalt. By coincidence, at the time of the episode's airing, Oswalt was starring on Happy! (2017) with former "SVU" leading man Christopher Meloni.
This is the final appearance of Ned Eisenberg on the series before his death in 2022.