Police officer Darren Wilson testified today in front of a grand jury convened to investigate the shooting death of unarmed Ferguson, Mo. teen Michael Brown last month.  

The St. Louis Post-Dispatch reported that Wilson, who wasn't under any legal obligation to testify before the grand jury, testified for four hours and was "cooperative." 

The grand jury proceedings are not open to the public, though they are being recorded, and prosecutors have said the recordings will be released to the public immediately if Wilson is not charged with a crime in Brown's shooting. If Wilson is charged, the recordings and transcripts will become evidence. 

Prosecutors will continue present evidence during the grand jury investigation, and the jury will decide whether to charge Wilson. That process is expected to take until mid-October. 

Wilson's testimony came a day after some called for prosecutor Bob McCulloch to be taken off the case. From the Associated Press:

Critics have questioned whether McCulloch should be removed from the case given his family history. McCulloch's father was a St. Louis police officer killed in the line of duty by a black assailant in the 1960s. McCulloch declined to step aside, and Gov. Jay Nixon declined to appoint a special prosecutor.

[Via Salon]