LAS VEGAS -- A Nevada Highway Patrol trooper was the driver in a fatal three-vehicle crash on South Rainbow Boulevard south of West Hacienda Avenue that may have been related to a medical condition, Metro police said.

At 1:34 p.m. Wednesday, witnesses reported a 2003 Chevrolet S-10 pickup truck being driven by Kevin Merrill, 26, of North Las Vegas, traveling northbound on South Rainbow Boulevard in the left of three travel lanes.

A 1991 Toyota Cressida driven by Manuel Ramirez, 50, of Las Vegas, was going southbound on South Rainbow Boulevard in the center two-way turn lane, preparing to turn left into an apartment complex.

A 2003 Ford F150 being driven by NHP Trooper Sgt. Edward Lattin, 46, of Las Vegas, was also southbound in the center two-way turn lane.

According to witnesses, the Ford F150 left the roadway just north of Tropicana Avenue and struck a street light pole before going through the intersection of Rainbow Boulevard and Tropicana Avenue. Witnesses reported the Ford continued southbound along the west curb before crossing all three southbound travel lanes into the center two-way turn lane.

Witnesses said Lattin failed to slow down as his truck approached the Toyota. The left front of the Ford struck the right rear of the Toyota. The Ford continued onto the trunk and roof of the Toyota, causing the Ford to roll over one time before coming to rest on its wheels facing a northeasterly direction, police said.

The Toyota rotated in a counterclockwise direction and struck the northbound Chevrolet S-10 before coming to rest facing an easterly direction, police said.

Lattin and Ramirez, as well as the female passenger in the Toyota, were transported to University Medical Center, where the drivers were treated for moderate injuries and released.

The female passenger, who was from Las Vegas, was pronounced dead shortly after arrival at UMC. Her name and age are being withheld pending notification of next of kin, police said.

Lattin voluntarily submitted to a blood draw which has been submitted to the Metro Crime Lab for testing.

Lattin has a medical history which may have contributed to the crash. A review of his medical records will be a part of the investigation. No criminal action has been taken pending further investigation.

Police said the NHP trooper was driving his personal truck at the time, not an NHP vehicle, and that he was off-duty.

Lattin is a supervisor and long-time veteran of NHP.

He told police he blacked out and did not know what happened and that it may have had to do with a medical issue.

Police said Lattin has a diabetic condition and that he was possibly in some type of a diabetic coma when the crash occurred.

This was the 56th fatal traffic accident in Metro's jurisdiction this year.