Two police officers allegedly identified a man charged with the murder of journalist Lyra McKee by his height, build and gait, the High Court has heard.
They claim to have recognised Paul McIntyre as being a masked figure at rioting surrounding the killing in Derry last year, a judge was told.
Prosecutors confirmed the identification evidence and clothing similarities forms the basis for suspecting the 52-year-old accused escorted the gunman to the scene of the shooting and then picked up his bullet casings.
But defence lawyers insisted the case against McIntrye was speculatively centred on 15 seconds of footage and failed to link him to any role in the killing.
Mark Mulholland QC contended: "It does not cross the Rubicon in order to even start to ground a reasonable suspicion of murder."
Competing submissions were advanced in an ongoing Public Prosecution Service appeal against McIntyre being granted bail.
Ms McKee, 29, was shot as she observed street disorder in the city's Creggan area on April 18.
Police came under attack from stones, petrol bombs and other missiles, while vehicles were also hijacked during the unrest said to have been orchestrated by members of the New IRA.
McIntrye, with an address at Kinnego Park in Derry, was initially charged with rioting, petrol bomb offences, and the arson of a tipper truck.
But last month he was further charged with the journalist's murder, possessing a firearm with intent to endanger life, and belonging to a proscribed organisation.
He remains in custody pending the outcome of the challenge to a magistrate's decision to admit him to bail.
The court heard he is allegedly identified by clothing on mobile phone and television footage from the night of the shooting.
According to the prosecution case, he is seen throwing and lighting petrol bombs, and emerging from the truck which was then set on fire.
When an unidentified gunman emerges later, he allegedly escorts him to the area where the shooting occurred.
It was claimed that McIntyre can be seen crouching down and picking up four cartridge cases ejected from the killer's weapon.
A forensic report has identified 17 points of reference where clothing McIntrye was seen in earlier in the day is allegedly comparable to that worn by the figure said to have escorted the gunman.
Setting out the basis for contending that a prima facie case has been established against McIntyre, Crown lawyer Robin Steer pointed to the report and statements from police.
He said: "There are two police officers able to identify this applicant by reason of his height, build and gait from the footage.
"That's the footage where we say he is the person we say is masked."
Mrs Justice Keegan was also told measurements carried out on a lamppost where a figure went past carrying a crate of petrol bombs allegedly corresponded with McIntyre'e height.
However, Mr Mulholland disputed the reliability of the forensic report and questioned whether it can be treated as expert evidence.
The barrister also claimed it was impossible to say McIntrye can be seen collecting four bullet casings based on a 15 second clip showing a group of people in the area.
In submissions he went on to challenge his client's alleged involvement in the murder as part of a joint venture.
"If we are down to the footage showing several people with masks on walking in the vicinity of what is a gunman, and several leaving with the gunman, if that is the basis upon which the prosecution seek to adduce Mr McIntyre as a secondary party, it is highly speculative," counsel argued.
Mr Steer confirmed in response that the murder charge is based on the accused's alleged role in bringing the gunman to the scene.
"I accept one cannot have a joint enterprise after the event, it's the escorting before the event and the circumstances surrounding that," he added.
Adjourning the appeal hearing, Mrs Justice Keegan said: "I will hopefully be able to give a ruling by the end of the week, but there are a few things I need to consider."