Complex sentence: Crown prosecutors had not immediately decided if they would pursue the charge of attempted murder upon securing a conviction of first degree murder since a conviction of attempted murder would not add to the life sentence Twitchell had already received.
Split into simpler sentences: Crown prosecutors had not immediately decided if they would pursue the charge of attempted murder upon securing a conviction of first degree murder. But a conviction of attempted murder would not add to the life sentence Twitchell had already received.