I have not conducted as extensive research on this topic as a number of companies, such as ASPI, the Australian Strategic Policy Institute, did last year. I specifically have information on Huawei and Nuctech. Also, the IPVM has published on this, on Hikvision specifically. Hikvision was clearly receiving public security tenders in Xinjiang. Hikvision is strongly implicated.
On July 20th, 2020. See this statement in context.