Things grew very heated inside of an Arkansas courtroom on Thursday when a distant relative of Josh Duggar took the stand in the former reality star's child pornography trial.

Not just heated, either.

Things grew controversial.

And, for the infamous defendant facing decades in prison for the heinous crimes he is accused of, they also may have grown optimistic for the first time this week.

The tension started shortly after Mathew Waller took the stand.

If the last name sounds familiar, you aren't imagining things.

A former colleague of Duggar's at the used car lot he worked at, Wholesale Motors, Waller is also related to the 19 Kids and Counting alum: his brother, David Waller, is married to Priscilla, the sister of Josh's wife, Anna.

Waller mostly testified in regard to a piece of software known as  a Linux partition on Josh's work computer, which effectively splits a hard drive in two.

According to Assistant U.S. Attorney Dustin Roberts, Duggar downloaded sexually graphic material of minors on the part of his hard drive this software helped to hide..

The prosecutor also said in his opening statement that the partitioned part of the computer had a different password from the main hard drive.

This password was Intel1988.

In simpler terms, the prosecution believes Duggar downloaded illicit videos and photos to a section of his computer only accessible with the password Intel1988.

We repeat this because it will soon become very important. Intel1988.

On Thursday, Waller said under oath that he worked for Duggar from late January through April of 2019, selling cars and doing some mechanical repairs.

During that time, what did he know about any illegal activities?

The former employee said that he only ever saw Josh use the keyboard that accessed his office, which is where the computer in question was located.

One of Duggar's defense lawyers, Travis Story, then questioned Roberts about the password on the partitioned harddrive, asking if Intel1988 rang a bell for him.

"Intel very faintly rings a bell," Waller responded.

At this, Robert jumped up from his table and screamed at the witness.

"I told you I thought you were hiding something, didn't I?" he said.

"I asked you specifically if you were intending to testify to something that you were not telling me," Roberts added, indicating that Waller previously said he didn't know the password.

"You're recalling today knowing about Intell1988, after talking to Homeland Security, then the defense?"

Waller reacted in confusion, saying the the word "intel" only sounded vaguely familiar and that he was having trouble keeping straight which attorneys represented Duggar and which the government.

Story eventually asked whether the defense simply instructed Waller to tell the truth on the stand.

Waller said yes.

Waller did, however, admit on the stand that the Duggar's legal team first mentioned the word "intel" during pre-trial questioning, prompting Roberts to imply defense had told him information he didn't otherwise remember.

This is all confusing, we know.

But here is why it's so crucial:

The unexpected testimony could be provide the jury with reasonable doubt.

If Waller was familiar with Duggar's password to access what amounts to the dark Web, then other employees also may have known this password.

And, conceivably, they could therefore have downloaded the pornography.

This is the crux of the defense team's argument.

They aren't attempting to prove that the grotesque videos downloaded to Josh's computer don't exist or were never on the computer.

Instead, they are simply trying to make it sound plausible that someone else downloaded the material.

Duggar's trial is expected to last five to six days.

Some of his immediate family members, including sister Jill (Duggar) Dillard and brother Jedidiah Duggar, are on the list to potentially take the stand as witnesses later on.

Their connection to the case is not clear.

If convicted of the charges against him?

Stay tuned.