The state has seen relatively few petitions for extreme risk protection orders since it passed its law in January 2020. One study found 109 filings in the first year. Chris Knoepke, a University of Colorado professor who has studied the issue, said data from 2021 and 2022 show a slight increase in usage. . . . “It’s heartbreaking when you hear one of these stories, and you worry that an opportunity was missed to potentially do something about it,” said Knoepke, who is working with state officials on developing training on ERPOs for Colorado law enforcement.