Authorities continue to investigate the circumstances surrounding a crash late Friday on Interstate 270 in Maryland that killed two public-safety officers.

Sander B. Cohen, 33, a deputy chief state fire marshal and a lieutenant with the Rockville Volunteer Fire Department, and Carlos Wolff, 36, a supervisory special agent in the District office of the FBI, were killed. Both were struck by a vehicle as they stood on the southbound shoulder of I-270, just north of Gude Drive in Montgomery County.

The impact threw Cohen and Wolff over the median of the roadway onto the northbound side of the interstate, where Cohen was struck by a second vehicle.

On Sunday, Maryland Gov. Larry Hogan (R) ordered that the state flag be flown at half-staff.

On Saturday, Hogan tweeted: "FBI Supervisory Special Agent Carlos Wolff & Lt. Sander Cohen, deputy chief of MD State Fire Marshal's Office & member of Rockville Vol Fire Dpt, served our communities every day to keep families safe. We thank these officers for their selfless dedication to our state & nation."

Officials said Wolff had been driving in the left lane of southbound I-270 when his Acura SUV apparently hit the median and became disabled about 10 p.m. Investigators said Cohen, who also had been driving southbound on the roadway, spotted Wolff's vehicle and reported the crash to state police. Officials said Cohen then positioned his vehicle to block Wolff's damaged vehicle, activated his emergency flashers and got out to help. Both men then moved to stand on the shoulder of the road, officials said.

Investigators said that was where the men were standing when a Honda Accord traveling southbound on I-270 apparently swerved to the left to avoid hitting the stopped vehicles and struck the men.

The driver of the southbound vehicle was identified as Roberto A. Garza Palacios, 28, of Germantown, Md. Palacios and two passengers, identified as Mirelia Y. Barcena Mormontoy, 23, of Germantown and Ada G. Sandoval Cortez, 32, of Clarksburg, Md., were taken to hospitals for treatment.

The driver of the northbound vehicle was identified as Brittany A. Waters, 32, of Clarksburg. Waters, who did not report being injured, remained at the scene.

No charges have been filed, and investigators do not think that the weather or alcohol were factors. Once the crash investigation is complete, it will be up to the Montgomery County State Attorney's Office to determine whether charges are filed.

FBI supervisory special agent Carlos Wolff with his wife, their 7-year-old son and 2-year-old daughter. Wolff was killed Friday along Interstate 270. (N/A/Family photo)

Investigators said it is not clear why Wolff's vehicle struck the concrete barrier.

Cohen, a decorated fire marshal, had been a member of the Office of the State Fire Marshal for nine years. In January, he was appointed regional commander of the Northern Regional Office, responsible for supervising fire investigations in Carroll, Harford and Cecil counties. He also was an active member with the Rockville Volunteer Fire Department, Station 33.

Wolff, an 11-year veteran of the FBI, who lived in Gaithersburg, was praised by his family as "an amazing father, husband, uncle and brother who made us all very proud."

In a statement, the family said: "He loved serving his country as a part of the FBI. He was always so helpful and giving, not just to his friends but strangers too. Our hearts are broken. We appreciate your prayers during this difficult time."

Wolff, the son of Maria and Jorge Wolff, was married and had two children, a 7-year-old son and a 2-year-old daughter. The American University graduate also leaves behind five siblings.