Two Canberra brothers faced court on Tuesday accused of involvement in their cousin's drug trafficking and attempting to conceal evidence.

Builders Youssef Jabal and Adam Ahmad Jabal are the cousins of Bilal Badr-Eddeen Omari, who worked at the Australian National University.

Police allege Mr Omari has been dealing in cocaine.

Documents tendered to court say that on December 5, police searched Mr Omari's ANU office.

Mr Omari told police he had not driven to work that day, but declined to comment on the Jeep keys in his pocket.

That afternoon, police told Mr Omari they had a search warrant for his car.

He called his girlfriend.

His girlfriend then called Youssef, 32, and this conversation was intercepted by police.

The documents allege that she told him police were going to be at "Billy's" car soon.

She allegedly told him to "Break it Youssef. Something. Like, he's got everything in his car."

Youssef replied: "Leave it with me. I'll work it out."

That afternoon, police went to the secure fenced car park at ANU where Mr Omari's car was parked.

On approach, they heard several loud bangs followed by a car alarm, the documents suggest.

An officer saw a man at the car wearing a black Adidas jumper and holding a black, straight tool.

He recognised the man as Adam Jabal, 27.

"Is that you Adam?" he called out.

"I can't hear you," the man replied.

The man then fled, the documents say.

When police got access to the car park and approached the car, they found a plastic shopping bag on the ground beneath the broken window.

Allegedly inside the bag was a plastic sandwich bag with 35 grams of alleged cocaine, another bag with 100 grams of cutting agent and digital scales.

In the car, police allegedly found $12,000 cash, multiple clip seal bags and multiple mobile phones.

That afternoon, police intercepted a phone call between Youssef and his mother.

Before the line connected Youssef is heard saying "take your jumper off".

He then told his mother he would bring Adam home.

In another intercepted phone call, he is heard saying "put it in the washing".

Other intercepted phone calls between Youssef and another man suggest he wanted a recording of the office for the last week, and that the recording must be time and date stamped.

On December 14, Youssef and Adam went with their lawyer and handed themselves into the police station.

In the ACT Magistrates Court on Tuesday, the Jabal brothers applied for bail for a second time.

Defence barrister Steven Whybrow said there was not such a strong Crown case "that [the brothers] knew Mr Omari was a drug dealer."

He said on the other charges they faced there was a presumption in favour of bail.

Prosecutors opposed their release.

Soraya Saikal-Skea, from the office of the ACT Director of Public Prosecutions, said the telephone intercepts were "damning".

She said that common sense suggested the pair had full knowledge of what was in Mr Omari's car.

But Special Magistrate Ken Cush said he would release the two brothers on strict conditions.

This included handing in their passports, not going near airports and reporting daily to police.

They have also been banned from contacting Mr Omari, his girlfriend, and Wright man Peter Edward Poulakis, 28.

Mr Omari has been charged with trafficking in a controlled drug, and the court also heard police were investigating the man for the alleged importation of drugs.

Youssef, of Crace, and Adam, of McKellar, have been charged with knowingly concerned traffic controlled drug, attempt destroy or conceal evidence and pervert the course of justice.

Adam has also been charged with the attempted possession of a drug of dependence.

Neither has entered pleas.

They are next due in court on January 16.