Dallas police said Tuesday afternoon a man was arrested in the murder of Joshua Brown, a key witness in the Amber Guyger murder trial, and two other suspects were on the run. Brown, 28, was found with multiple gunshot wounds in a parking lot about four miles from the apartment where Botham Jean was gunned down. In that case, which attracted national attention, Guyger, a former police officer, was convicted of Jean's murder and sentenced to 10 years in prison. Assistant Chief Avery Moore said three suspects — Jacquerious Mitchell, 20; Michael Mitchell, 32; and Thaddeous Green, 22 — were...