As Russian forces closed in on Hostomel in late February, the town's mayor Yurii Prylypko urged local residents to take care of each other.

“I'm here with you. We have to resist," he said in a video message. “The weapons are coming. Our soldiers are coming. We will get through this. We just need to keep calm and protect the people around us. Thank you!”

Days later, Prylypko was dead. He and another civilian, Ivan Zorya, were killed by Russian soldiers, eyewitnesses say, as they tried to deliver medicines and other supplies to people in the community. Another civilian, Oleksandr Karpenko, was killed while trying to save them.

Russia has consistently denied targeting civilians during its invasion of Ukraine.

But photos of the scene taken in its aftermath and images captured by security cameras on the day of the attack make it clear the mayor was traveling in a civilian car when Russian troops opened fire. There were no other cars or military vehicles nearby at the time, according to the eyewitnesses.

CNN has requested an official comment from the Russian Defense Ministry on the Hostomel killings, but has not received a response.

As part of an investigation into the three men's deaths, CNN spoke to three eyewitnesses to the attack on March 3 and to several other local residents who saw Prylypko's and Zorya's bodies lying on the street in the days following the shooting.

his picture from a security camera in the courtyard of the Pokrovsky residential complex shows Russian troops were active in the area on Thursday, March 3, 2022.

Russian soldiers in the courtyard of the Pokrovsky residential complex in an image taken from the security camera on Thursday, March 3, 2022. A letter V is visible on the armored vehicle.

Hostomel lies some 15 miles (25 kilometers) northwest of Kyiv, on one of the main roads leading to the Ukrainian capital. It was the site of some of the worst fighting in the early days of the conflict. The cargo airport of the same name -- just north of Hostomel town center -- was targeted by Russian troops on the very first day of the war.

Hostomel -- like Irpin, Bucha, Vorzel and other towns, villages and suburbs north of Kyiv -- came under Russian control soon after the invasion began. When Ukraine regained control of the area at the end of March, those names became synonymous with the atrocities committed by Russian troops during the occupation.

Among those atrocities: The widespread and apparently deliberate killing of civilians. The deaths of Prylypko, Zorya and Karpenko fit this pattern, according to the accounts of witnesses and survivors.

When Hostomel came under attack, Prylypko organized a team of about a dozen volunteers tasked with delivering food, medicines and other supplies to the people hiding out in shelters around the town, according to Prylypko's family and several of the volunteers involved in the operation.

On March 3, the eighth day of the invasion, Prylypko and three other volunteers set off in a white Renault Duster SUV from his home in the town's west.

Taras Kuzmak, the head of Hostomel's municipal utility company, was driving the car. He told CNN the mayor sat next to him in the front seat as the group headed east. He said none of the men in the vehicle was armed or wore body armor.

Yuri Shturma, another of the volunteers who was with Prylypko inside the car, said the mayor was trying to arrange the delivery of power generators for Hostomel, since by that point -- in the depths of the Ukrainian winter -- the town had been cut off from electricity, water and heating for days.

Prylypko believed a humanitarian convoy was due to arrive in Hostomel from the south that day, according to Shturma.

As the car passed the municipal lake and approached the main road running through Hostomel, the volunteers spotted a column of Russian tanks to the east, Shturma and Kuzmak told CNN.

At that time, the southern part of Hostomel, some two miles away, was still under Ukrainian control. But the town's north had been taken over by Russian troops, who were edging closer to the town center.

According to a report from the Ukrainian Defense Ministry's intelligence directorate, Russian and Ukrainian troops were battling for control of Hostomel near the town's glass factory -- less than a mile from the volunteers' car -- at the time.

“And that's where we came under fire for the first time,” Kuzmak said.

The volunteers tried to flee, speeding away and turning south, but it was too late. Zorya, who was sitting in the back seat of the car, had been shot in the head. He collapsed onto Shturma, who was sitting next to him, bleeding heavily.

“The wound was right in his head. You can imagine when they shoot at the head from a heavy machine gun,” Kuzmak said.

Shturma said the men saw an armored vehicle with the letter “V” -- one of the signs known to be used by the Russian military alongside the more notorious “Z” marking -- written on its side as they tried to get away.

When he realized the extent of Zorya's injuries, Prylypko ordered the car to head to a medical clinic in a nearby residential complex, Kuzmak told CNN.

But what the group in the car didn't know was that the complex had already been taken over by the Russians.

Images taken from security cameras inside the Pokrovsky complex and shared with CNN show a number of Russian troops huddled in the yard and aiming heavy weapons at something outside the frame. It is unclear what their target was at that time, but the image makes it clear the Russian were active in the area on that day.

“The Russians were already there,” Kuzmak told CNN. “There were about seven armored vehicles in the yard, tanks, and infantry fighting vehicles. It was heavy equipment.”

Kuzmak and Shturma said it was at this moment that their car came under attack once again.

“When we jumped out of the car, they started shooting at us again from the Pokrovsky. I pulled Ivan out of the car. They started shooting at us from automatic weapons from the distance of 50 meters, maybe less,” Shturma said.

It was at this point that Prylypko was hit, as he tried to find cover, Kuzmak and Shturma told CNN.

The pair said they had taken shelter behind an excavator that had been left behind after a local construction company tried to demolish a bridge over a stream to slow down the Russian advance. (CNN)

•PHOTO: Russian soldiers in the courtyard of the Pokrovsky residential complex in an image taken from the security camera on Thursday, March 3, 2022. A letter V is visible on the armored vehicle.

Update news