POOLESVILLE, Md. - A 27-year-old man has died after being struck by a vehicle in an early-morning hit-and-run in Poolesville, turning what authorities initially described as a critical-injury crash into a fatal collision investigation.

Montgomery County police said officers responded at approximately 1:51 a.m. Sunday to the area of Fisher Avenue and Milford Mill Road after receiving a report that a pedestrian had been struck.

The department's preliminary investigation indicates that an unknown vehicle struck the man near 19630 Fisher Avenue. The driver left the scene and had not been located as of the latest police update.

The pedestrian suffered life-threatening injuries and was taken to an area hospital. Police later confirmed that he died from those injuries.

Earlier reports Sunday morning described the victim as critically injured. WJLA updated its report at 12:34 p.m. to reflect that authorities now say the 27-year-old died.

Driver believed to have fled west

Detectives believe the driver traveled westbound on Fisher Avenue toward Elgin Road after the collision.

Police have not publicly released a description of the vehicle involved, a license plate number or identifying information about the driver. That leaves the identity of the striking vehicle and the person behind the wheel as the central unresolved questions in the investigation.

The Montgomery County Police Department's Collision Reconstruction Unit is handling the case. The unit investigates serious and fatal crashes and works to reconstruct factors including vehicle movement, roadway evidence and the sequence of events leading to a collision.

The victim's name had not been released as of the latest update. Police said additional information, including his identity, would be provided after his next of kin had been properly notified.

Crash occurred along Fisher Avenue

The collision happened near the 19600 block of Fisher Avenue, a commercial section of Poolesville. Police identified the area near 19630 Fisher Avenue as the location where the pedestrian was struck.

The MoCo Show reported that Montgomery County Fire and Rescue Service personnel and police responded to the scene shortly before 2 a.m. The victim was initially transported as a Priority 1 trauma patient with life-threatening injuries.

Emergency activity temporarily affected lanes in the area during the initial response.

FOX 5 reported that police have not indicated what type of vehicle struck the man or described what led up to the collision. The available information also does not establish where the pedestrian was positioned in relation to the travel lanes when he was hit.

Those details could become important as investigators determine the circumstances of the crash and attempt to identify the driver.

Investigation remains active

The fatality confirmation significantly changes the status of the case from the first reports issued Sunday morning. The investigation is now centered on a fatal hit-and-run in which the driver remains unidentified and at large.

No arrest had been announced as of Sunday afternoon, and police had not publicly identified a suspect.

Authorities also had not released photographs or surveillance footage of the suspected vehicle in connection with the crash. In other fatal hit-and-run investigations, Montgomery County police have sometimes released vehicle descriptions or images after investigators develop additional evidence, but officials have not said whether such evidence is available in this case.

For now, the confirmed sequence is limited: officers were called at about 1:51 a.m., investigators believe an unknown vehicle struck the 27-year-old near 19630 Fisher Avenue, the driver left westbound toward Elgin Road, and the pedestrian later died at a hospital.

Montgomery County police said more information will be released as it becomes available. The Collision Reconstruction Unit's investigation remains active.