Kouri Richins, a Utah mother accused of murdering her husband and later publishing a children's book about grief, has been found guilty on all charges by a jury in Utah.The jury deliberated for about three hours on Monday before returning the verdict.Richins, 35, faced multiple felony charges for allegedly poisoning Eric Richins, her late husband, in March 2022. Prosecutors said she mixed and served him a Moscow Mule cocktail she had allegedly spiked with a lethal dose of fentanyl at their home just outside of Park City. The drink contained nearly five times what is considered a deadly amount of the opioid, court filings showed. The most serious counts against Richins, for aggravated murder and attempted aggravated murder, carry maximum sentences of life in prison. Richins also faced additional charges for mortgage fraud and forgery, after she allegedly signed to close on a multimillion-dollar real estate deal the day after her husband died.…