Sgt. George Mendez struck 72-year-old Steven Christy on Pleasant Street on Nov. 25.
Christy was taken to a hospital and died from his injuries five days later.
The state Office of Special Investigation found no evidence that Mendez was speeding, distracted, using his cellphone, impaired by drugs or alcohol or otherwise driving dangerously at the time of the crash.
However, the report raised concerns about how the crash was investigated.
Investigators found that Mendez’s vehicle was unregistered, uninspected and did not have a front license plate.
It was later determined that authorities did not thoroughly inspect the vehicle, examine its event data recorder or request assistance from an outside agency trained in collision reconstruction.
According to the Attorney General's office, the Sullivan County Sheriff’s Office allowed Mendez to drive the vehicle away from the scene and did not issue tickets until authorities learned Christy was in critical condition and was not expected to survive.
The report also noted that none of the responding Monticello police officers or Sullivan County sheriff’s deputies were equipped with body-worn cameras.