Via TRAC:

Despite rising numbers of individuals detained by Immigration and Customs Enforcement (ICE), fewer and fewer individuals who have committed and been convicted of serious crimes are among them. Recently released case-by-case ICE records of those in ICE custody at the end of various months during the past four years document that the number of those who have been convicted of what ICE characterizes as the most serious, or Level 1 offenses[1], have been falling steadily since 2017.