They are prosecution exhibits 317 A, B, F, G, H, L and T, photos of individual frames from security video inside Aaron Hernandez's home; grainy still shots that could doom the defense of the former New England Patriot in the 2013 murder of his friend, Odin Lloyd.

They are the non-smoking gun, if you will.

Police never found the murder weapon, a Glock 21 Generation 3, linked to the shooting death of Lloyd. His body was found with six bullet wounds in a field behind an industrial park near Hernandez's North Attleboro, Mass., home. Five casings were discovered on the scene. A sixth was found inside a Nissan Altima that Hernandez rented and is seen on videotape driving that night.

The still photos from around 3:30 a.m. on June 17, 2013, just minutes after the prosecution's painstakingly constructed timeline says that Lloyd was killed, show Hernandez in the foyer of his home, about to head down to his man cave in the basement, holding a black object that stands starkly against his white shirt.

It looks like a gun. Prosecutors contend it's a gun. And in perhaps the most critical stretch of this now seven-week-old trial at Bristol County (Mass.) Superior Court, jurors on Wednesday listened as a Glock expert testified that, in his opinion, it is a gun.

"In my opinion, the firearm shown in the video still is a Glock pistol," Kyle Aspinwall, a district sales manager and product representative from Glock, testified.

The defense, which has argued that it might be a remote control or even a black iPod in Hernandez's hand, vigorously opposed Aspinwall being able to offer his opinion, arguing to Judge E. Susan Garsh that his testimony would be both prejudicial and unreliable because Aspinwall is not a gun designer. Garsh denied the motion Wednesday.

And so the prosecution continued, presenting to the jury both the exhibits and a real life Glock 21 Gen 3, the same make and model police say slayed Lloyd.

Aspinwall painstakingly went through each image, as well as others from different angles, and described precisely what he saw.

There's the somewhat distinctive design of the back strap of the weapon in 317 A, visible because Hernandez, Aspinwall contends, is holding the gun by the barrel. There is Glock's signature curvature of the back strap – a "French curl," Aspinwall described it – that is clear in 317 F. There's the trigger guard and front strap seen in the angle of 317 T.

"Salient features," stated Aspinwall, a former small-town New Hampshire police chief.

The defense had previously lost arguments to keep this evidence and testimony out of the trial altogether. The defense especially objected to allowing Aspinwall to hold up a Glock Gen 3, Model 21 for the jury.

"[It's] highly inflammatory and invites unfounded jury speculation," the defense previously argued. Garsh ruled for the Commonwealth then and did again Wednesday.

This was clearly an effort to display the de facto murder weapon, which the prosecution has implied was disposed of the following day by Hernandez's live-in girlfriend, Shayanna Jenkins, who is the mother of his young daughter.

None of this was good for Hernandez. There is no denying the power behind video of him walking around his home minutes after the alleged murder carrying what at the very least appears to be a weapon. It likely didn't take an expert for the jury to see a gun in Hernandez's hand. This may be circumstantial evidence, but it's extremely strong circumstantial evidence.

Worse for the defense, further video shows Hernandez retrieved the black object from the rented Nissan after he parked it in the driveway.

If it is, indeed, a remote control, why was it in Hernandez's car?

The prosecution curiously finished up with Aspinwall just before the scheduled 1 p.m. ET end of testimony for the day, allowing defense attorney James Sultan to get in 14 minutes of what was expected to be a vigorous cross-examination. Had it stalled questioning for a little longer, the prosecution could have sent the jury home for the night without a word of the defense reaching them.

Instead Sultan was able to get Aspinwall to acknowledge that there are other guns, including from other manufacturers, in the market that are similar in appearance to the Glock 21 Gen 3.

Thursday's full day of testimony should feature a full-on attack by the defense, which is well aware that if it can't raise reasonable doubt about the object in Hernandez's hand – either that it might be a different weapon or something else – then its case is in dire straits.

For Aaron Hernandez and his defense, the mountain to climb just got steeper.