There have been urgent calls for investigations into allegations of war crimes in previously Russian-held areas of Ukraine after shocking footage of murdered civilians. But there are wider questions over whether widespread Russian attacks on civilian targets amount to war crimes. We've been looking at a series of attacks in one city - Chernihiv - to see whether they are consistent with Russian tactics across Ukraine and reveal something of their strategy. 1: Direct targeting of civilians "They were shooting at us with everything they had," says Diana, 20. Within minutes of encountering the Russian tank, half her family would be dead. Diana, her mother Irina, her partner Sasha and his little brother Maxim were fleeing Chernihiv on 9 March after weeks of shelling. They had one simple aim - to reach safety in the west of the country, where relatives were waiting for them. But within minutes of leaving the city heading south they were plunged into danger. As their Volkswagen Golf passed the village of Kolychivka, Sasha saw Russian tanks ahead. One fired at them immediately. He put his foot down, hoping to accelerate through the danger zone - and then the car stalled. The firing continued, and Sasha shouted for them get out - but 15-year-old Maxim had already been hit. There was a hole in his chest and blood coming from his mouth. Diana, Sasha and Irina crawled into bushes - but soldiers were approaching, shouting to each other, asking where the family were hiding. Bullets cracked towards them. Diana's foot was seriously injured. Sasha tried to bandage it, but then as he turned to help Irina, the horror worsened. "Irina opened her jacket and we realised that there was nothing to bandage," Diana told BBC News. "A part of her abdomen and intestines had been shot through." They heard more shooting and Diana turned to Sasha believing these were their final minutes. "We had time to say that we loved each other," she said. "I asked Sasha, 'Are we going to die here?' He said, 'Probably'. "My mum crawled with us a little more. I kept turning and saying, 'Mum, crawl, please, please'. She said, 'Yes, yes'. And then she [lay] down on the ground. She died there." Diana kept crawling, following Sasha as he broke a path for her through the thicket. They went past a burning field and through the forest. Diana and Sasha survived and she made it to a hospital. She has lost four toes from her left foot. Diana has no doubt the attackers were Russian because of their accents, uniforms and the Z symbol daubed on one of the tanks. The AFP verification team has found no evidence of any legitimate military targets near the site of the attack. 2: Cutting off basic services Water is the most basic of human necessities and there is evidence of deliberate Russian targeting of the supply in Chernihiv. A pumping station on the outskirts of the city was hit on 14 March. The attack badly damaged a water reservoir and destroyed a control room, according to the head of the water company in Chernihiv, Serhiy Malyavko, who said a worker at the plant - along with three family members - were killed. The family was sheltering there after their home was destroyed by shelling. Satellite imagery shows the damage to the plant, located by Twitter user @obretix in a forested area far away from other buildings. Photos released by the water company showed a severely damaged treatment tank with small craters in the ground. Damage that looks like shrapnel holes pepper the buildings. The sequence of craters visible in a satellite image suggests ground-launched strikes, says Wim Zwijnenburg, a Dutch arms researcher. "The shrapnel impact and blast direction seem to indicate the missiles were fired from the west of the water facility, [which] corresponds with the presence of Russian troop movements located to the west, according to public data on their locations." Without access to the site itself, the experts we've spoken to say it's not possible to be precise about the weapons used. Rather than missiles, the damage may have been caused by heavy guns or mortars. The head of the water company says the site was struck three days in a row. "There was no military target. I'm 100% sure that the Russian troops have been destroying the city's infrastructure so that there would be no gas, no electricity or water supply in the city," Mr Malyavko told AFP News. He said two other facilities elsewhere were also destroyed, cutting off water to most of the city's population. The rules of war ban premeditated attacks on targets indispensable to civilian life, such as water supplies. "This has been done to make the population panic," says Mr Malyavko. "And Russia is probably hoping that if there's a humanitarian catastrophe, the local authorities will agree to start negotiations - and that the city will surrender."