(CNN) -- During his trip to northwest Syria in late April, Ole Solvang talked to dozens of people who told him gut-wrenching stories. When the Human Rights Watch interviewer and his colleagues returned home, they titled their report "They burned my heart: War crimes in Northern Idlib during peace plan negotiations." "Those words were chosen because what we saw and heard evidence of were systematic executions and torture -- war crimes -- by the Syrian government forces," he said. "It's been frustrating to record these stories and then hear more negotiating," said Solvang, who describes in a video what he saw. "I think it's clear that there are attempts to undermine the peace plan."
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Human Rights Watch interviewed Syrians who said families had been executed
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One woman talked about finding her son's body, tortured, in a cemetery
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The group interviewed 65 witnesses and victims in late April
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Interviewer said what he heard and saw constitutes war crimes
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His regime has banned foreign journalists, and several of those who've attempted to report on what's happening in @placeholder have been injured or killed.