A jury is now deciding the fate of the man who was once Suffolk's top prosecutor and his former top aide.

The defense attorney for former Suffolk District Attorney Thomas Spota began his closing arguments Thursday, saying that the prosecution took “a deep dive into an ocean of speculation.”

Spota and his top aide Christopher McPartland are on trial for allegedly helping to conceal former Police Chief James Burke’s assault on a prisoner in 2012.

RELATED: Prosecution focuses on ex-lieutenant’s testimony in Spota trial closing arguments 

Alan Vinegrad, Spota’s attorney, also discredited the government’s star witness, James Hickey - a lieutenant in the Suffolk County Police Department at the time of Christopher Loeb’s beating.

Vinegrad reminded jurors that Hickey admitted he lied on the stand in a separate trial in the 1990s and had four extramarital affairs.

“Bear in mind, Jim Hickey is a man with a long track record of lying when it is in his best interest to lie,” said Vinegrad.

Hickey had testified that he had direct conversations with Spota and McPartland about the alleged cover-up.

During the government's rebuttal, prosecutor Lara Gatz reminded jurors that there are two kinds of evidence – direct and circumstantial. She then put up a list of 23 things she said just doesn’t make sense if Spota and McPartland were not taking part in the cover-up.

She says that list includes items that witnesses, other than Hickey, testified to, such as:

On Monday, the jury will be charged, or given instructions, by the judge about what they can consider under the law. They should be deliberating by Monday afternoon.