Authorities "haven't ruled out" the possibility that the stabbing at a manufacturing company in Michigan was motivated by the UnitedHealthcare CEO shooting.
Richard Allen, 52, was sentenced Friday to 130 years in prison for the stabbing deaths of 13-year-old Abby Williams and 14-year-old Libby German in 2017.
Brett and Nikki Cross clashed with police officers while trying to enter a pretrial hearing for a former police chief. Their son was among 19 kids killed at the school.
Authorities in Madison said they are looking into the 15-year-old assailant's online activity, as well as a purported manifesto and potential bullying.
Prosecutors said Nima Momeni planned the attack on Lee, driving him to an isolated spot under the Bay Bridge and stabbing him three times with a knife.
The unidentified owner of the three XL bully dogs died at a hospital last week after they attacked him at a children's playground despite the efforts of onlookers.