Convicted Killer of Brother from Toms River Dies Behind Bars

Convicted Killer of Brother from Toms River Dies Behind Bars

In March, Matthew Hertgen was acquitted of his brother Joseph's murder due to insanity.

Earlier this month, the man who killed his younger brother in their Princeton apartment last year passed away.

On May 8, 32-year-old Matthew Hertgen was discovered dead in the Mercer County jail. Authorities told NJ.com that Matthew appeared to have committed suicide. A report on the autopsy is still pending.

Since calling 911 in February 2025 to report the death of his 27-year-old brother Joseph Hertgen in their Princeton apartment with Michelle Mews, Matthew has been detained.

Judge Robert Lytle of the Mercer County Superior Court determined that Matthew was legally insane at the time of the incident and ruled him not guilty by reason of insanity on March 19. Prosecutors said they were unable to challenge this ruling.

When police arrived on the site in the evening of February 22, 2025, they discovered Joseph, his brother, lying on the ground in a pool of blood with deep cuts and serious blunt force injuries. A golf club was lying next to the corpse. Following his arrest, Matthew reported to the police that he had "gone into a fit of crazy, maybe like forty minutes earlier." Joseph began working as an analyst for Locust Point Capital in Red Bank in 2023 after graduating from Toms River North in 2016.

In an obituary, his family recalled a different guy, one who was fashioned by love, intelligence, and faith but whose last years were marked by disease.

"During his final years, Matthew struggled with serious and profound mental health issues; but he demonstrated grief, remorse, and repentance in many ways," his family stated. "He departed with the love, friendship, and forgiveness of his family. May he rest in peace.