RCMP Const. Joshua Penton wasn't on duty when he dropped by the Whitehorse detachment to check emails when he heard of a shooting in Haines Junction involving Cpl. Kim MacKellar.

Penton told a Yukon Supreme Court jury Tuesday he asked the commanding officer if he could be of assistance.

He was immediately dispatched on the morning of Sept. 26, 2011 in an unmarked police van, only having time to throw his bullet-proof vest and gun belt over his civilian clothes.

Penton said he ended up spending the day and days afterward cataloguing and collecting items seized by investigators.

It was the freshman constable of a year and a half back then who photographed and removed a rifle from the moss near the Pine Lake Campground that morning.

The .375 H & H shell ejected from the rifle by Penton to neutralize the firearm was photographed and catalogued by him, he told the jury.

Several hours after Penton and Sgt. Jim Giczi were called to the site of the rifle by the police dog handler, Penton was recording a swab taken by Giczi from the handle of a safe lying in the parking lot of Madley's General Store, the jury heard.

Penton testified he commandeered Cpl. MacKellar's office at the Haines Junction RCMP detachment for his temporary and secure evidence locker.

He slept in the office on an air mattress the night of Sept. 26.

When he wasn't there, the office door was secured by an unmistakable seal, the jury heard.

Under questioning from Crown prosecutor Keith Parkkari, Penton testified he never left the evidence unattended, and never had an issue with the door seal.

"Do you have any reason to believe the exhibits had been tampered with?” Parkkari asked.

"Absolutely not,” the constable replied.

Christopher Cornell, 31, and Jessica Johnson, 22, were charged on Sept. 26, 2011 with attempting to murder MacKellar and Shane Oakley by shooting at them with a rifle during a high-speed chase.

They were also charged with using violence and bear spray while stealing a safe from Madley's.

Only Cornell is on trial at this time.

The jury has heard how, in the dark morning hours of Sept. 26, MacKellar and Oakley, a deputy conservation officer, ended up chasing a black SUV from the front of Madley's store down the Alaska Highway toward Destruction Bay.

The chase ended with what Oakley described for the jury last week as an explosion of glass inside the marked RCMP truck.

The jury has also heard how Cornell and a woman hitched a ride to the Pine Lake Campground from their broken-down vehicle, located about half way between Haines Junction and Destruction Bay.

Penton spent most of Tuesday going through exhibit after exhibit, in meticulous detail.

He told of cataloguing a yellow RCMP patrol jacket with metal fragments stuck to it, and metal fragments taken from the driver's door on MacKellar's police truck.

The jury was shown a radar module typically mounted inside police vehicles. Jurors were told of fragments of what appeared to be electronic material.

Penton had catalogued a spent .375 H & H magnum rifle shell recovered by Giczi on Sept. 29 from the rear of a black Chevrolet Blazer while the "suspect” vehicle was being inspected inside the identification bay at the Whitehorse detachment.

An unspent or live .375 H & H round was also seized by Giczi from the suspect vehicle, the jury heard.

Penton testified of another spent .375 H & H round seized from a Suzuki Sidekick SUV involved in the investigation.

Jurors heard of six hypodermic needles removed from the suspect Blazer.

The five needles from the glove box all had protective caps over the needle point, but the one removed from the door pocket did not, the jury heard.

Penton said two crack pipes were also seized from the Blazer's glove box.

Multiple cookie and candy wrappers strewn throughout the cab were bagged and tagged, he told the jury.

The jury heard how, on the evening of Sept. 26, Penton seized two hypodermic needles from the general store's parking lot.

Another needle was seized at the arrest site from the pocket of a hoodie being worn by Johnson.

Penton said another syringe and crack pipe were seized from Johnson's backpack, along with four live .375 H & H rounds, a cell phone and a variety of candies.

Among the items inside a dark green Omega travel bag seized at the arrest site were three cans of bear spray, two knives, clothing, cookies, candies, miniature chocolate bars and cash.