TRENTON — A state grand jury has voted not to file criminal charges against a New Jersey State Police (NJSP) trooper at the conclusion of its deliberations regarding an August 13, 2024 fatal crash during a vehicle pursuit in Hope Township, Warren County. Michael J. Ceddia, Jr., 76, of Hackettstown, New Jersey, died in the crash after his motorcycle was struck by an SUV fleeing from the trooper. The SUV that hit the victim’s motorcycle was driven by Sean B. Mamakas, 33, of Kempton, Pennsylvania.
Mr. Ceddia’s death was investigated by the Office of Public Integrity and Accountability (OPIA) and presented to New Jersey residents serving on the grand jury in accordance with the Independent Prosecutor Directive of 2019. In July 2021, OPIA issued standard operating procedures (SOPs) to ensure these grand jury presentations are conducted in a neutral, objective manner, with appropriate transparency regarding the process, consistent with the directive.
The investigation included video footage from a motor vehicle recorder and body-worn camera, radio transmissions, witness statements, and autopsy results from the medical examiner. This evidence, including video of the incident, was presented to a state grand jury. After hearing the testimony and evidence, the grand jury finished deliberating on May 20, 2025, and voted “no bill,” concluding no criminal charges should be filed against NJSP Trooper Christopher Bird.
According to the investigation, at approximately 10:19 a.m. on August 13, 2024, Trooper Bird began following a grey Ford Explorer SUV on Route 80 eastbound in the area of milepost 11. Trooper Bird activated his lights and sirens to conduct a motor vehicle stop of the Explorer. The driver of the SUV, Mr. Mamakas, fled eastbound on the right shoulder of the interstate at a high speed. Trooper Bird initiated a pursuit and Mr. Mamakas took Exit 12, exiting onto County Road 521 south in Hope Township.
At approximately 10:20 a.m., Mr. Mamakas’ Explorer passed a civilian vehicle on the left in an oncoming lane of traffic in the area of Dogwood Road before the Explorer merged back into the southbound lane, where it impacted Mr. Ceddia’s motorcycle, which was traveling south on County Road 521. The impact caused Mr. Ceddia to be ejected from his motorcycle. After the collision, Mr. Mamakas’ Explorer went off the road and came to a stop in a wooded area.
Medical aid was administered to Mr. Ceddia, who ultimately succumbed to his injuries and was pronounced dead at the scene. Mr. Mamakas was transported for a medical evaluation to Hackettstown Medical Center and later released into police custody.
OPIA designated the Warren County Prosecutor’s Office to handle the investigation of Mr. Mamakas’ conduct. In March 2025, a Warren County grand jury indicted Mr. Mamakas on charges of aggravated manslaughter, death by auto, eluding, aggravated assault, and possession of a controlled dangerous substance (CDS). The charges are pending. These charges and allegations are merely accusations, and Mr. Mamakas is presumed innocent unless and until proven guilty in court.
The Attorney General’s Office today released footage from a police body-worn camera and a mobile video recorder related to the fatal crash. The footage is being released pursuant to policies established by the Attorney General’s Office in 2019 designed to promote the fair, impartial, and transparent investigation of fatal police encounters. Investigators previously met with representatives of Mr. Ceddia’s family to review the recordings.
The recordings are available here: https://njoag.box.com/s/tixqnlkhgh9aqs1i22qchqnlblj05j60
A 2019 law, N.J.S.A. 52:17B-107(a)(2), requires the Attorney General’s Office to conduct investigations of a person’s death that occurs during an encounter with a law enforcement officer acting in the officer’s official capacity or while the decedent is in custody. It requires that all such investigations be presented to a grand jury to determine if the evidence supports the return of an indictment against the officer or officers involved. The grand jury is instructed on the elements of the potential criminal offenses, including criminal homicide offenses, that could be brought and, as required by statutes, the grand jury is instructed on self-defense and other forms of legal justification.
A conflicts check was conducted pursuant to the Independent Prosecutor Directive and no actual or potential conflict of interest was found involving any individual assigned to the investigation. Prior to presentation to the grand jury, the investigation was reviewed by OPIA Executive Director Drew Skinner in accordance with the policies and procedures established for these presentations in the SOPs.
At the conclusion of these investigations, pursuant to the Independent Prosecutor Directive and SOPs, OPIA determines whether any principal should be referred to the appropriate law enforcement agency for administrative review in accordance with the AG’s Internal Affairs Policy & Procedures. OPIA monitors any resulting review and takes such actions as are necessary to ensure that the review is completed in a timely fashion, and that appropriate actions are taken based on the results of the review.
