Complex sentence: Some media reports have suggested that he underwent conversion to Islam while in prison, after which he changed his name to Khalid Masood, though police have said he also used several other aliases, including Khalid Choudry, and that he wasn't radicalised in prison.
Split into simpler sentences: Some media reports have suggested that he underwent conversion to Islam while in prison, after which he changed his name to Khalid Masood. Police have said he also used several other aliases, including Khalid Choudry, and that he was not radicalised in prison.