Toronto shooting on streetcar

Eighteen-year-old Sammy Yatim was shot nine times, Tasered, and killed by Toronto police early Saturday morning. It is unlikely that many details will emerge any time soon. And if history is an indicator, many of the details may never be known, unless there is a public inquiry. But while members of the police are required, by law, to co-operate with the SIU investigation, there are a great many obstacles that are likely to hamper the SIU's work. Here are some.