Pc Terry, a father of two from Burnley, Lancashire, was shot as the unit practised in a disused factory in Newton Heath on June 9 2008.
An inquest held at Manchester Coroner's Court in March 2010 found Pc Terry was unlawfully killed.
More top news
Fine, dry start. Turning unsettled, wettest on Wednesday - but with the unsettled weather, it will turn warmer!
Merseyside Police have confirmed that a police investigation is underway following the explosion in Wirral yesterday.
Fine, dry and sunny again on Sunday! High pressure still in charge...