ABC News' Luis Martinez and Serena Marshall report:

Bradley Manning's pre-trial hearing  to determine whether he should face a court martial for leaking thousands of classified documents to WikiLeaks is nearing its conclusion.  The fifth day of the Article 32 hearing promises to build on Monday's testimony that linked Manning to the anti-secrecy website and its founder Julian Assange.

Government prosecutors are expected to wrap up their witness list today as they present their final six witnesses. Manning's defense team is expected to then call its three witnesses.

At Monday's hearing, Army investigators described how they had found evidence that Manning might have been in communication with WikiLeaks and Assange.

One said a review of Manning's personal computer turned up two email addresses linked to Assange as part of an Internet chat buddy list.

They also discovered an email Manning had sent to an acquaintance in which he claimed to have provided WikiLeaks with video from a 2007 Apache helicopter attack in Baghdad that resulted in civilian casualties.

One of the investigators described having found hundreds of thousands of Iraq and Afghanistan battlefield reports on a data card that Manning used on his secure work computers. 

Accompanying the files was a message from Manning describing the documents as "possibly one of the more significant documents of our time, removing the fog of war and revealing the true nature of 21st century asymmetric warfare."

He even recommended sitting on the documents for three to six months to determine the best way of distributing them to a wider audience and to protect the source.

Once the government calls all its witnesses, it will rest its case, giving the defense the opportunity to call the first of its witnesses. On the first day of the hearing last Friday, Manning's attorneys complained about how the investigating officer presiding over the case had accepted all of the prosecution's 21 witnesses, but granted only a fraction of the 48 witnesses the defense wanted to testify.

Manning's defense team is expected to call three witnesses. After a recess, both sides will be given time to create their closing arguments, which is basically a summary of evidence presented and whether the burden for "reasonable belief" has been met.

The Article 32 hearing taking place at Fort Meade, Md., is the military's version of a grand jury to decide whether to take his case to a court martial.   The only outcomes would be a recommendation for a court-martial proceeding or "other disposition," which means some other Army demotion or the sort, or dismiss the charges.

If the investigating officer recommends the case to court-martial the sworn testimony in these hearings could be used; but more likely they would call everyone back to the witness stand.  

The charges against Manning call for the death penalty, but government prosecutors have repeatedly said that they will seek life in prison instead.